1 Neuroanatomy, Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, INF 307, D-69120 Heidelberg, Germany
2 IGBMC,CNRS/INSERM/Université Louis Pasteur, BP 163, 67404 Illkirch Cédex, Cu de Strasbourg, France
3 Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75239-9148, USA
*Author for correspondence (e-mail: klaus.unsicker{at}urz.uni-heidelberg.de)
Accepted 8 July 2002
![]() |
SUMMARY |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Key words: Sympathoadrenal cell lineage, Neuroendocrine cells, Chromaffin phenotype, Phox2b, Mouse
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
A variety of transcription factors have been identified to be involved in the development of the SA cell lineage. Mash1 (Ascl1 Mouse Genome Informatics) the mammalian homologue of Asc genes in Drosophila (Johnson et al., 1990), plays a key role in the development of the autonomic cell lineage (Guillemot et al., 1993
; Hirsch et al., 1998
; Lo et al., 1998
), including the SA cell lineage. SA progenitors transiently express MASH1 when they form the primary sympathetic anlagen (Lo et al., 1991
). Homozygous mice carrying targeted mutations in the Mash1 locus (Mash1/ mice) are non-viable and show severe deficits in virtually all peripheral, but also central catecholaminergic neurons (Guillemot et al., 1993
; Hirsch et al., 1998
). Although SA cells in Mash1-deficient mice aggregate at the dorsal aorta, they fail to undergo their complete differentiation program and finally die (Guillemot et al., 1993
; Sommer et al., 1995
; Hirsch et al., 1998
).
A variety of genes have been shown to be directly or indirectly regulated by MASH1 in SA cells. The transcription factor Phox2a (Arix Mouse Genome Informatics) (Tiveron et al., 1996; Valarché et al., 1993
; Morin et al., 1997
), which induces TH and dopamine-ß-hydroxylase (DBH) (two enzymes involved in the catecholaminergic pathway), is not expressed in the absence of MASH1 (Hirsch et al., 1998
; Lo et al., 1998
). By contrast, the functionally and evolutionary closely related transcription factor Phox2b (Pmx2b Mouse Genome Informatics) (Pattyn et al., 1997
), is expressed in the absence of MASH1 (Hirsch et al., 1998
).
Inconsistent with the idea that MASH1 is required for an early differentiation step of NC cells into a bipotential TH-positive SA progenitor, it has been reported that only the neuronal progeny of the SA lineage is largely eliminated in Mash1-deficient mice. Chromaffin cells in the adrenal gland have been reported to be only weakly affected by the mutation (Guillemot et al., 1993). If correct, this result raises the possibility of identifying, at the molecular level, novel and putatively distinct developmental requirements of sympathetic neurons and chromaffin cells. However, the present study demonstrates that the vast majority of adrenal chromaffin cells depends on MASH1 function for their development. Most cells in the adrenal medulla of Mash1/ mice lack chromaffin granules, resemble sympathetic neuroblasts, and, similar to wild-type sympathetic neurons, express neurofilament and Ret. Our findings suggest that the development of chomaffin cells does depend on MASH1 function not only for catecholaminergic differentiation, but also for general chromaffin cell differentiation.
![]() |
MATERIALS AND METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Histology
Pregnant mice were killed by CO2 asphyxation. Embryos were recovered, rinsed with phosphate-buffered saline (PBS, pH 7.4) and fixed in PBS containing 4% paraformaldehyde (PFA) for 4-12 hours depending on the developmental age and further processing. Newborn mice were transcardially perfused with 4% PFA, adrenals were removed and postfixed for 4 hours. After fixation, the tissue was either processed for freezing or paraffin embedding. To prepare cryosections, tissues were rinsed three times with phosphate buffer and then placed in 30% sucrose in PBS for cryoprotection. After overnight immersion in sucrose, the tissue was coated with OCTTM compound (Tissue Tek), frozen on dry-ice and stored at 70°C until further processing. The tissue was then cut into 12 µm serial sections, mounted on SuperfrostTM slides and air dried for 30 minutes, before performing in situ hybridization or immunofluorescence staining. For paraffin embedding after fixation, tissues were rinsed three times in PBS, dehydrated through increasing concentrations of ethanol before embedding in paraffin wax. Serial sections (7 µm) were mounted on silane-coated slides and dried at 37°C.
Immunofluorescence staining
Antibodies and immunoreagents were obtained from the following sources (dilution and required references in brackets): polyclonal sheep anti-tyrosine hydroxylase (TH, 1:200; Chemicon International, Temecula, CA); polyclonal rabbit anti-phenylethanolamine-N-methyl-transferase (PNMT, 1:2000, Incstar, Stillwater, OK); normal goat serum, normal rabbit serum and biotinylated goat anti-rabbit antibody were obtained from Vector Laboratories; and Cy3TM-conjugated-anti-sheep antibody, Cy3TM-conjugated-anti-sheep antibody, Cy2TM-conjugated anti rabbit antibody and Cy2TM-conjugated streptavidin were obtained from Dianova, Hamburg, Germany. Antibodies to the transcription factor Phox2b (1:100) (Pattyn et al., 1997) were kindly provided by Drs Jean-Francois Brunet and Christo Goridis, IBDM, Marseille, France.
For immunofluorescence-staining sections were pretreated with 10% serum corresponding to the secondary antibody, in PBS and 0.1% Triton X-100, followed by overnight incubation with primary antibody at 4°C. Then sections were rinsed in PBS and incubated with a Cy3TM- or Cy2TM-conjugated secondary antibody respectively (1:200) for 2 hours at room temperature. Sections were then rinsed in PBS and mounted with Fluorescent Mounting Medium (Dako). For Phox2b and TH double immunostaining freshly cut cryosections were incubated overnight in PBS at 70°C. After 30 minutes blocking with 20% FCS in PBS and 0.1% Tween-20 sections were incubated with rabbit anti-Phox2b antibody overnight at 4°C. Sections were then rinsed with PBS and incubated with biotinylated anti-rabbit antibody (1:200) for 2 hours at room temperature, followed by 1 hours incubation with Cy2TM-conjugated streptavidin. TH immunostaining was then carried out as described above.
In situ hybridization
Non-radioactive in situ hybridization on cryosections and preparation of digoxigenin-labeled probes for mouse TH (Zhou et al., 1995), mouse Ret (Pachnis et al., 1993
), mouse MASH1 (Casarosa et al., 1999
), mouse Hand2 (Srivastava et al., 1997
), mouse Phox2a (Valarché et al., 1993
) and neurofilament 68 were carried out using a modification of the protocol of D. Henrique (IRFDBU, Oxford, UK) as previously described (Ernsberger et al., 1997
). Mouse neurofilament 68 (bp: 855-1549) was cloned by PCR using a pGEM-T vector system following the manufacturers instructions. The plasmid was linearized with SacII (antisense) and SacI (sense control) and transcribed with Sp6 (antisense) and T7 (sense control).
TdT dUTP nick end labeling (TUNEL) analysis
For detection of apoptotic adrenal medullary cells, TUNEL was performed on 12 µm cryosections using an ApoTag TM In Situ APOPTOSIS Detection Kit (Oncor, Gaithesburg, MD) according to the manufacturers instructions as previously described (Finotto et al., 1999). Three mice for each group were analyzed.
Electronmicroscopy
For electronmicroscopy, adrenals from E14.5 and E16.5 embryos were fixed by immersion in a mixture of glutaraldehyde (1.5%) and paraformaldehyde (1.5%) in phosphate buffer at pH 7.3 for 48 hours and rinsed several times with cacodylate buffer (0.1 M). Organs were then postfixed in 1% OsO4 /1.5% potassium hexacyanoferrate, rinsed in 0.1 M cacodylate buffer and 0.2 M sodium maleate buffer (pH 6.0) and block-stained with 1% uranyl acetate. After dehydration through increasing concentrations of ethanol, the tissue was Epon embedded. Ultrathin sections (50 nm) were examined with a Zeiss EM10.
![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
|
|
|
|
|
|
|
|
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Several lines of evidence support the notion that sympathetic neurons and neuroendocrine cells share a common progenitor (Anderson et al., 1991; Anderson, 1993
; Unsicker, 1993
). It was surprising, therefore, that chromaffin cells were reported not to be overtly affected by the MASH1 mutation (Guillemot et al., 1993
), possibly arguing against the postulated close developmental relationship of sympathetic neurons and chromaffin cells. Moreover, these data also raised the possiblity of identifying, at a molecular level, novel and putatively distinct developmental requirements of sympathetic neurons and neuroendocrine chromaffin cells.
One fundamental difference in the molecular pathways that generate sympathetic neuronal and chromaffin cells has previously been attributed to glucocorticoids (Unsicker et al., 1978; Doupe et al., 1985
; Anderson and Axel, 1986
; Anderson and Michelsohn, 1989
; Michelsohn and Anderson, 1992
). However, analysis of glucocorticoid receptor deficient mice had clearly shown that chromaffin cell development is largely normal even in the absence of glucocorticoid signaling (Finotto et al., 1999
) arguing in favor of putative alternative signals for the development of neuroendocrine chromaffin cells.
Deficiency in MASH1 affects a major subpopulation of adrenal chromaffin cells
The re-investigation of Mash1 mutant mice reported in this study has established that MASH1 is essential for survival, development of catecholaminergic traits, and correct morphological specification of a majority of adrenal chromaffin cells. Most adrenal medullary cells in Mash1/ mice failed to express TH and therefore could only be identified by their expression of Phox2b. On an ultrastructural level, most adrenal medullary cells lacked the typical ultrastructural features of chromaffin cells, i.e. the large secretory vesicles (Coupland, 1972; Coupland and Tomlinson, 1989
; Finotto et al., 1999
). These cells resembled very early neuroblasts, as described in embryonic sympathetic ganglia (Eränkö, 1972
). From E16.5 onwards, signs of degeneration and massive loss of cells became apparent. However, about 15% of the cells survived and expressed TH at birth. Approximately half of this population even expressed PNMT, indicating that a small subpopulation of adrenal chromaffin cells escapes differentiation arrest and death and maturates normally.
The requirement of MASH1 for the development of a majority of chromaffin cells is consistent with the expression of MASH1 mRNA in the mouse adrenal gland visualized by in situ hybridization until at E16.5 (this study), and the expression of the chick homolog CASH1 in chick adrenal gland until at least E8 (Ernsberger et al., 1995). MASH1 is also expressed in SA progenitor cells along the dorsal aorta (Guillemot and Joyner, 1993
; Lo et al., 1991
) prior to their migration into secondary sympathetic ganglia and adrenal gland, but is strongly downregulated in secondary sympathetic ganglia (Guillemot and Joyner, 1993
; Lo et al., 1991
).
Previous analyses of Mash1 deficient mice have provided evidence for generation, determination and differentiation functions in neuronal lineages
MASH1 has been implicated in a variety of aspects of early and late neuronal development, depending, in part, on the region of the nervous system investigated. Mice lacking Mash1 present defects in the specification of progenitor cells in autonomic ganglia, olfactory epithelium and ventral forebrain. Thus, in the olfactory epithelium of Mash1 mutant mice, primary neuroepithelial progenitors are present but fail to generate secondary progenitors with a neuronal identity (Cau et al., 1997). Similarly, defects in neurogenesis in the ventral telencephalon in Mash1 mutant mice severely affects the subventricular zone, which contains mostly committed progenitor cells, rather than the ventricular zone, where neural stem cells are located (Casarosa et al., 1999
).
In the peripheral sympathetic system, sympathetic neuroblasts can be identified in Mash1 mutant mice during the earliest stage of formation of primary sympathetic anlagen (E10 to 10.5) along the dorsal aorta, albeit at reduced numbers. The cells do not express Phox2a, but their expression of Phox2b is not affected (Hirsch et al., 1998). As shown in the present study, chromaffin progenitor cells lacking MASH1 do express Phox2a, thus resembling the few sympathetic neuroblasts that, in Mash1 mutants, survive up to E13.5 (Hirsch et al., 1998
). Moreover, MASH1-deficient chromaffin progenitor cells also expressed Hand2, suggesting that deficiencies in Phox2b, Phox2a and Hand2 are unlikely to account for the loss of TH in these cells.
Analyses of the cellular function of MASH1 in the development of autonomic neurons also suggest that MASH1 does not commit neural crest cells to a neural fate (Sommer et al., 1995). In the absence of MASH1, autonomic neuronal precursors express a number of neuron-specific genes, such as neurofilament and neuron-specific ß-tubulin. However, further differentiation into neurons that express the intermediate filaments peripherin and SCG10 requires MASH1. The phenotype of sympathetic ganglia in Mash1 mutant mice can therefore be explained by the arrest of neuronal development at this precursor stage.
With regard to the neuroendocrine progeny of the neural crest, i.e. chromaffin cells and thyroid C cells (Le Douarin and Kalcheim, 1999), it has previously been shown that Mash1 mutant mice have a greatly reduced number of C cells that lack calcitonin and serotonergic markers (Lanigan et al., 1997
).
A putative scenario for a MASH1 requirement in chromaffin cell development
Our results clearly show that SA progenitor cells expressing Phox2b have invaded the adrenal anlagen by E13.5 in Mash1 mutant mice and still exist at numbers almost identical to wild-type littermates at E14.5. This suggests that migration of progenitors from the dorsal aorta to their final target is not impaired in the absence of MASH1. Moreover, this observation indicates that almost the full set of SA progenitors has managed to survive within the adrenal gland of Mash1-deficient mice at a time, when almost all their counterparts in paravertebral sympathetic ganglia have disappeared, based on Phox2b immunoreactivity and neurofilament in situ hybridization (Hirsch et al., 1998; this study). Similarly, in Phox2b/lacZ mutant mice paravertebral sympathetic neurons cannot be detected in paravertebral ganglia at E13.5, whereas the adrenal medulla appears morphologically intact at this time and expresses lacZ (Pattyn et al.,1999
). Together, these two sets of data suggest that SA progenitors that have populated the adrenal gland are distinct in their differentiation program from SA progenitors committed to a sympathetic neuronal fate either already prior to or immediately after their immigration into the adrenal gland (Anderson and Axel, 1986
; Anderson, 1993
). Alternatively, SA progenitors may respond to specific adrenal cues promoting their survival immediately upon invading the adrenal gland.
The first overt deficit that we have seen at E13.5 with SA progenitor cells within the adrenal gland of MASH1-deficient mice is the lack of TH immunoreactivity in about 60% of the Phox2b-positive cells. At this time, sympathetic neurons in MASH1 mutant mice already display a more severe phenotype: paravertebral sympathetic ganglia in anterior thoracic regions completely lack TH as early as E12.5, while only few residual TH-positive cells can be found in posterior regions (Guillemot et al., 1993). Thus, SA progenitors visualized by Phox2b are not only present in the adrenal gland early in almost full numbers, about half of them have been able to progress in their differentiation program up to the level of TH expression. In Mash1+/+ mice, about 25% of the Phox2b-positive sympathoadrenal cells inside the adrenal gland do not express TH at detectable levels at the time of their immigration and apparently continue their differentiation after arrival in their target organ. Thus, the observed defect in TH expression in some intra-adrenal progenitor cells of Mash1 mutant mice indicates that MASH1 may be essential for at least a subset of cells immediately after their immigration.
Starting at E16.5, i.e. at a time when differentiation of chromaffin cells in the adrenal gland has progressed [e.g. by the initiation of PNMT expression in a subpopulation of cells and by a further increase in size and numbers of the specific chromaffin granules (Finotto et al., 1999)], deficits in the development of the MASH1-deficient adrenal medulla become more dramatic. In the absence of MASH1, numbers of Phox2b- and TH-positive cells have failed to increase. This indicates that in normal chromaffin cell development MASH1 is a prerequisite for increasing the size of the population and for their maintenance. This notion is also supported by the substantial number of TUNEL-positive medullary cells in Mash1 mutants starting at E16.5.
Beyond the numerical deficit and lack of TH in many adrenal medullary cells, the failure of most SA cells in the adrenal gland to extinguish neuronal and acquire neuroendocrine features (Anderson, 1993; Michelsohn and Anderson, 1992
; Unsicker, 1993
) is the most intriguing finding in the adrenals of Mash1 mutants. Maintenance of high levels of expression of neurofilament mRNA matching those seen in wild-type sympathetic ganglia, and maintenance of Ret mRNA as seen in sympathetic ganglia (Pachnis et al., 1993
; Hirsch et al., 1998
), suggest that the development of most adrenal medullary has been arrested at the level of immature sympathetic neurons or, at least, has been strongly retarded. This notion is further corroborated by the observation that numerous medullary cells exhibit ultrastructural features of immature neuroblasts. Thus, the developmental deficit seen in a majority of adrenal medullary cells of Mash1 mutants parallels that seen with sympathetic neurons: sympathetic neurons progress up to the expression of a number of neuronal genes, including neurofilament and neuron-specific tubulin, but then fail to proceed to the level of peripherin and SCG10 expression (Sommer et al., 1995
). Similarly, most adrenal medullary cells of Mash1 mutants express neurofilament, but fail to undergo further differentiation. Thus, MASH1 is apparently required in most adrenal medullary cells to differentiate beyond the early neuroblast stage, which includes conversion into the neuroendocrine phenotype. Accordingly, MASH1 is necessary to reach an advanced neuroblast stage irrespective of whether this is in the neuronal or neuroendocrine differentiation pathway.
Our results also indicate that a subpopulation of MASH1-deficient adrenal medullary cells progresses in differentiation towards the relatively mature chromaffin phenotype with typical ultrastructural and biochemical features, such as large chromaffin granules, expression of PNMT, and extinction of neurofilament and Ret. Similarly, a fraction of sympathoblasts has been shown to escape MASH1 dependency and acquires a mature sympathetic neuron phenotype (Hirsch et al., 1998). Whether the few surviving chromaffin cells are entirely independent from MASH1, or would require MASH1 to complete postnatal differentiation, remains to be studied. Thus, our results also suggest that adrenal medullary progenitors may be genetically less homogeneous than widely believed. To begin to address the molecular bases of this heterogeneity, we investigated transcription factors Phox2b, Phox2a and Hand2. However, their expression was not restricted to TH-positive chromaffin cells and apparently occurred in all or most chromaffin progenitor cells of Mash1 mutant mice. This suggests that expression of Phox2b, Phox2a and Hand2 are unlikely to account for the heterogeneity of chromaffin cells. However, we cannot exclude dose differences in translation products of these factors as putative reasons for heterogeneity of chromaffin cells.
In summary, the present study demonstrates both similarities and differences of chromaffin cells and sympathetic neurons in their dependency on MASH1. Our data support the notion that MASH1 holds a key position not only in neuronal, but also in neuroendocrine differentiation programs. However, a subpopulation of chromaffin cells seems to be independent from MASH1 and rely on other factor(s) that remain to be identified.
![]() |
ACKNOWLEDGMENTS |
---|
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Airaksinen, M., Titievsky, A. and Saarma, M. (1999). GDNF family neurotrophic factor signaling: four Masters, one servant. Mol. Cell. Neurosci. 13, 313-325.[CrossRef][Medline]
Anderson, D. J. (1993). Molecular control of cell fate in the neural crest: the sympathoadrenal lineage. Annu. Rev. Neurosci. 16, 129-158.[CrossRef][Medline]
Anderson, D. J. and Axel, R. (1986). A bipotential neuroendocrine precursor whose choice of cell fate is determined by NGF and glucocorticoids. Cell 47, 1079-1090.[Medline]
Anderson, D. J. and Michelsohn, A. (1989). Role of glucocorticoids in the chromaffin-neuron developmental decision. Int. J. Dev. Neurosci. 12, 83-94.
Anderson, D. J., Carnahan, J. F., Michelsohn, A. and Patterson, P. (1991). Antibody markers identify a common progenitor to sympathetic neurons and chromaffin cells in vivo and reveal the timing of commitment to neuronal differentiation in the sympathoadrenal lineage. J. Neurosci. 11, 3507-3519.[Abstract]
Blaugrund, E., Pham, T. D., Tennyson, V. M., Lo, L., Sommer, L., Anderson, D. J. and Gershon, M. D. (1996). Distinct subpopulations of enteric neuronal progenitors defined by time of development, sympathoadrenal lineage markers and Mash-1-dependence. Development 122, 309-320.
Casarosa, S., Fode, C. and Guillemot, F. (1999). Mash1 regulates neurogenesis in the ventral telencephalon. Development 126, 525-534.
Cau, E., Gradwohl, G., Fode, C. and Guillemot, F. (1997). Mash1 activates a cascade of bHLH regulators in olfactory neuron progenitors. Development 124, 1611-1621.
Coupland, R. E. (1972). The chromaffin system. In Catecholamines Handbook of Experimental Pharmacology. Vol 33 (ed. H. Blaschko and E. Muscholl), pp 16-45. Berlin, Heidelberg, New York: Springer Verlag.
Coupland, R. E. and Tomlinson, A. (1989). The development and maturation of adrenal medullary chromaffin cells of the rat in vivo: a descriptive and quantitative study. Int. J. Dev. Neurosci. 7, 419-438.[CrossRef][Medline]
Deimling, F., Finotto, S., Lindner, K., Brühl, B., Roig-Lopez, J. L., Garcia-Arraras, J. E., Goridis, C., Kriegelstein, K. and Unsicker, K. (1998). Characterization of adrenal chromaffin progenitor cells in mice. Adv. Pharmacol. 42, 932-935.[Medline]
Doupe, A. J., Landis, S. C. and Patterson, P. H. (1985). Environmental influences in the development of neural crest derivatives: glucocorticoids, growth factors and chromaffin cell plasticity. J. Neurosci. 5, 2119-2142.[Abstract]
Eränkö, L. (1972). Ultrastructure of the developing sympathetic nerve cell and the storage of catecholamines. Brain Res. 46, 159-175.[CrossRef][Medline]
Ernsberger, U., Patzke, H., Tissier-Seta, J.-P., Reh, T., Goridis, C. and Rohrer, H. (1995). The expression of tyrosine hydroxylase and the transcription factors cPhox-2 and Cash-1: evidence for distinct inductive steps in the differentiation of chick sympathetic precursor cells. Mech. Dev. 52, 125-136.[CrossRef][Medline]
Ernsberger, U., Patzke, H. and Rohrer, H. (1997). The developmental expression of choline acetyltransferase (ChAT) and the neuropeptide VIP in chick sympathetic neurons: evidence for different regulatory events in cholinergic differentiation. Mech. Dev. 68, 115-126.[CrossRef][Medline]
Ernsberger, U., Reissmann, E., Mason, I. and Rohrer, H. (2000). The expression of dopamine beta-hydroxylase, tyrosine hydroxylase, and Phox2 transcription factors in sympathetic neurons: evidence for common regulation during noradrenergic induction and diverging regulation later in development. Mech. Dev. 92, 169-177.[CrossRef][Medline]
Finotto, S., Krieglstein, K., Schober, A., Deimling, F., Lindner, K., Brühl, B., Beier, K., Metz, J., Garcia-Arraras, J. E. et al. (1999). Analysis of mice carrying targeted mutations of the glucocorticoid receptor gene argues against an essential role of glucocorticoid signalling for generating adrenal chromaffin cells. Development 126, 2935-2944.
Ghysen, A., Dambly-Chaudière, C., Jan, L. Y. and Jan, Y. N. (1993). Cell interactions and gene interactions in peripheral neurogenesis. Genes Dev. 7, 723-733.[CrossRef][Medline]
Goldstein, M., Fuxe, K., Hökfelt, T. and Joh, T. H. (1971). Immunohistochemical studies on phenyletanolamine-N-methyltransferase, dopa-decarboxylase and dopamine-ß-hydroxylase. Experimentia 27, 951-952.[Medline]
Guillemot, F. and Joyner, A. L. (1993). Dynamic expression of the murine Achaete-Scute homologue Mash-1 in the developing nervous system. Mech. Dev. 42, 171-185.[CrossRef][Medline]
Guillemot, F., Lo, L.-C., Johnson, J. E., Auerbach, A., Anderson, D. J. and Joyner, A. L. (1993). Mammalian achaete-scute homolog 1 is required for the early development of olfactory and autonomic neurons. Cell 75, 463-476.[Medline]
Hirsch, M.-R., Tiveron, M.-C., Guillemot, G., Brunet, J.-F. and Goridis, C. (1998). Control of noradrenergic differentiation by MASH-1 in the central and peripheral nervous system. Development 125, 599-608.
Howard, M., Foster, D. N. and Cserjesi, P. (1999). Expression of HAND gene products may be sufficient for the differentiation of avian crest-derived cells into catecholaminergic neurons in culture. Dev. Biol. 215, 62-77.[CrossRef][Medline]
Jan, Y. N. and Jan, L. Y. (1994). Genetic control of cell fate specification in Drosophila peripheral nervous system. Annu. Rev. Genet. 28, 373-393.[CrossRef][Medline]
Johnson, J. E., Birren, S. J. and Anderson, D. J. (1990). Two rat homologues of Drosophila achaete-scute specifically expressed in neuronal precursors. Nature 346, 858-861.[CrossRef][Medline]
Landis, S. C. and Patterson, P. H. (1981). Neural crest cell lineages. Trends Neurol. Sci. 4, 172-175.[CrossRef]
Lanigan, T. M., DeRaad, S. K. and Russo, A. F. (1998). Requirement of the MASH-1 transcription factor for neuroendocrine differentiation of thyroid C cells. J. Neurobiol. 34, 126-134.[CrossRef][Medline]
Le Douarin, N. M. and Kalcheim, C. (1999). The Neural Crest, 2nd edn. Cambridge: Cambridge University Press.
Lo, L.-C., Johnson, J. E., Wuenschell, C. W., Saito, T. and Anderson, D. J. (1991). Mammalian achaete-scute homolog 1 is transiently expressed by spatially restricted subsets of early neuroepithelial and neural crest cells. Genes Dev. 5, 1524-1537.[Abstract]
Lo, L., Tiveron, M.-C. and Anderson, D. J. (1998). MASH1 activates expression of the paired homeodomain transcription factor Phox2a, and couples pan-neuronal and subtype-specific components of autonomic neuronal identity. Development 125, 609-620.
Michelsohn, A. M. and Anderson, D. J. (1992). Changes in competence determine the timing of two sequential glucocorticoid effects on sympathoadrenal progenitors. Neuron 8, 589-604.[Medline]
Morin, X., Cremer, H., Hirsch, M.-R., Kapur, R. P., Goridis, C. and Brunet, J.-F. (1997). Defects in sensory and autonomic ganglia and absence of locus coeruleus in mice deficient for the homeobox gene Phox2a. Neuron 18, 411-423.[CrossRef][Medline]
Nieto, M., Schuurmans, C., Britz, O. and Guillemot, F. (2001). Neural bHLH genes control the neuronal versus glial fate decision in cortical progenitors. Neuron 29, 401-413.[Medline]
Pachnis, V., Mankoo, B. and Costantini, F. (1993). Expression of the c-ret proto-oncogene during mouse embryogenesis. Development 119, 1005-1017.
Pattyn, A., Morin, X., Cremer, H., Goridis, C. and Brunet, J.-F. (1997). Expression and interactions of the two closely related homeobox genes Phox2a and Phox2b during neurogenesis. Development 124, 4065-4075.
Pattyn, A., Morin, X., Cremer, H., Goridis, C. and Brunet, J.-F. (1999). The homeobox gene Phox2b is essential for the development of autonomic neural crest derivatives. Nature 399, 366-370.[CrossRef][Medline]
Reissmann, E., Ernsberger, U., Francis-West, P. H., Rueger, D., Brickell, P. M. and Rohrer, H. (1996). Involvement of bone morphogenetic protein-4 and bone morphogenetic protein-7 in the differentiation of the adrenergic phenotype in developing sympathetic neurons. Development 122, 2079-2088.
Schneider, C., Wicht, H., Enderich, J., Wegner, M. and Rohrer, H. (1999). Bone morphogenetic proteins are required in vivo for the generation of sympathetic neurons. Neuron 24, 861-879.[Medline]
Schober, A., Arumäe, U., Saarma, M. and Unsicker, K. (2000). Expression of GFR-1, GFR
-2 and c-Ret mRNAs in rat adrenal gland. J. Neurocytol. 29, 209-213.[Medline]
Shah, N. M., Groves, A. K. and Anderson, D. J. (1996). Alternative neural crest cell fates are instructively promoted by TGF beta superfamily members. Cell 85, 331-343.[Medline]
Sommer, L., Shah, N., Mahendra, R. and Anderson, D. J. (1995). The cellular function of MASH1 in autonomic neurogenesis. Neuron 15, 1245-1258.[Medline]
Srivastava, D., Thomas, T., Lin, Q., Kirby, M. L., Brown, D. and Olson, E. N. (1997). Regulation of cardiac mesodermal and neural crest development by the bHLH transcription factor, dHAND. Nat. Genet. 16, 154-160.[Medline]
Stanke, M., Junghans, D., Geissen, M., Goridis, C., Ernsberger, U. and Rohrer, H. (1999). The Phox2 homeodomain proteins are sufficient to promote the development of sympathetic neurons. Development 126, 4087-4094.
Tiveron, M.-C., Hirsch, M.-R. and Brunet, J.-F. (1996). The expression pattern of the transcription factor Phox2 delineates synaptic pathways of the autonomic nervous system. J. Neurosci. 16, 7649-7660.
Unsicker, K., Krisch, B., Otten, J. and Thoenen, H. (1978). Nerve growth factor-induced fiber outgrowth from isolated rat adrenal chromaffin cells: Impairment by glucocorticoids. Proc. Natl. Acad. Sci. USA 75, 3498-3502.[Abstract]
Unsicker, K. (1993). The chromaffin cell: paradigm in cell, developmental, and growth factor biology. J. Anat. 183, 207-221.[Medline]
Valarché, I., Tissier-Seta, J.-P., Hirsch, M.-R., Martinez, S., Goridis, C. and Brunet, J.-F. (1993). The mouse homeodomain protein Phox2 regulates Ncam promoter activity in concert with Cux/CDP and is a putative determinant of neurotransmitter phenotype. Development 119, 881-896.
Vogel, K. S. and Weston, J. A. (1990). The sympathoadrenal lineage in avian embryos. II. Effects of glucocorticoids on cultured neural crest cells. Dev. Biol. 139, 13-23.[Medline]
Zhou, Q. Y., Quaife, C. J. and Palmiter, R. D. (1995). Targeted disruption of the tyrosine hydroxylase gene reveals that catecholamines are required for mouse fetal development. Nature 374, 640-643.[CrossRef][Medline]