Accumulation of the mitochondrial form of the sulphydryl oxidase Erv1p/Alrp during the early stages of spermatogenesis
1 Institut für Botanik, Heinrich-Heine-Universität
Düsseldorf, Universitätsstraße, D-40225 Düsseldorf,
Germany
2 Institut für Genetik, Heinrich-Heine-Universität
Düsseldorf, Universitätsstraße, D-40225 Düsseldorf,
Germany
* Author for correspondence (e-mail: lisowsky{at}uni-duesseldorf.de )
Accepted 1 May 2002
![]() |
Summary |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Key words: rat, mouse, sulphydryl oxidase, Erv1p/Alrp, spermatogenesis, mitochondria, iron/sulphur cluster
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Previous studies have demonstrated that different forms of Alrp may have
different cellular functions. After partial hepatectomy, a 15kDa Alrp fragment
accumulates in the cytosol and serum of regenerating liver
(Francavilla et al., 1994;
Giorda et al., 1996
;
Hagiya et al., 1994
;
Wang et al., 1999
).
Accumulation of this 15 kDa carboxyl-terminal fragment, which still retains
the enzymatic activity of a sulphydryl oxidase
(Lisowsky et al., 2001
),
correlates with a reduction in interferon-gamma levels, a reduction in the
lytic activity of natural killer cells and an increase in levels of
mitochondrial transcription factor A (TFAM) (Polimeno et al.,
2000a
,b
).
Overexpression of TFAM results in the production of greater amounts of
proteins for the respiratory chain and, thereby, increases the oxidative
phosphorylation capacity of mitochondria
(Polimeno et al., 2000b
), but
the functional correlation between the expression of the 15 kDa Alrp fragment
and the process of liver regeneration remains unclear.
So far, studies on mammalian Alrp have been dominated by its specific role
as an extracellular factor in liver regeneration
(Francavilla et al., 1994;
Gandhi et al., 1999
;
Wang et al., 1999
). We know
that, under normal conditions, the vast majority of Alrp is located inside
cells and that Alrp expression is not restricted to liver tissue
(Hofhaus et al., 1999
;
Lange et al., 2001
). Our
latest studies identified Alrp as a ubiquitous eukaryotic protein
(Hofhaus et al., 1999
;
Lange et al., 2001
;
Lisowsky et al., 2001
;
Polimeno et al., 1999
). Under
normal conditions, the full-length 23 kDa mammalian Alrp is predominant and
localized in the mitochondrial intermembrane space. In this compartment, Alrp
performs an essential function in the biogenesis of cytosolic iron/sulphur
cluster (Fe/S) proteins and is important for cellular iron homeostasis
(Lange et al., 2001
).
Therefore, participation in the assembly of cytosolic Fe/S proteins appears to
be the primary essential task of mitochondrial full-length Alrp
(Lange et al., 2001
). This
function is crucial for all eukaryotic cell types, whereas the proposed role
of 15 kDa Alrp as a hepatotrophic growth factor is restricted to liver cells,
and it may be effective only after cell damage. This indicates that Alrp, like
other redox-active proteins and sulphydryl oxidases
(Chivers et al., 1997
;
Kobayashi and Ito, 1999
;
Nakamura et al., 1997
;
Tanaka et al., 1997
), may have
diverse functions in the regulation of cell growth and differentiation
(Francavilla et al., 1994
;
Gandhi et al., 1999
;
Li et al., 2000
;
Polimeno et al., 1999
;
Wang et al., 1999
).
A consequence of these new data is the necessity to extend studies on
mammalian Alrp to different tissues, organs and developmental processes. The
finding that Alrp messenger RNA is synthesized in large amounts in the testis
(Giorda et al., 1996;
Hagiya et al., 1994
) turned
our attention to spermatogenesis. In addition, biochemical and
immunohistochemical studies had indicated the important role of other
sulphydryl oxidases for testicular differentiation processes
(Benayoun et al., 2001
;
Meinhardt et al., 1999
;
Oehmen et al., 1992
). Possible
functions of sulphydryl oxidases and other redox-active proteins in growth
regulation, differentiation, changes in mitochondrial and cellular membrane
morphology and in the formation of the extracellular matrix have already been
proposed (Benayoun et al.,
2001
; Coppock et al.,
1998
; Hoober et al.,
1999b
; Hoober and Thorpe,
1999
; Lee et al.,
2000
; Lisowsky,
2001
; Lisowsky et al.,
2001
; Meinhardt et al.,
1999
; Nakamura et al.,
1997
).
For our molecular analyses, a major breakthrough was the recent isolation
and sequencing of rat seminal vesicle FAD-dependent sulphydryl oxidase
(Benayoun et al., 2001). The
derived protein sequence identified the rat enzyme as highly homologous to
human and chicken Q6 sulphydryl oxidases. In fact, it appears plausible that
rat seminal vesicle FAD-dependent sulphydryl oxidase is synthesized from an
alternative splicing product of the Q6 messenger RNA
(Benayoun et al., 2001
). Human
Q6 and rat seminal vesicle FAD-linked enzymes are clearly distinct from the
Erv1p/Alrp sulphydryl oxidases. The Q6-related enzymes are monomeric proteins
larger than 60 kDa that are excreted from cells
(Benayoun et al., 2001
;
Coppock et al., 1998
). In
contrast, Erv1p/Alrp are small proteins of approximately 20 kDa that form
dimers normally localized in the mitochondrial intermembrane space
(Lee et al., 2000
;
Lange et al., 2001
). Weak
sequence homologies between Q6 and Erv1p/Alrp are restricted to the common
ERV1 prototype domain harbouring the redox-active centre of these enzymes.
This domain of approximately 100 amino acid residues contains the
CXXC motif essential for disulphide bridge formation activity
(Hoober and Thorpe, 1999
;
Lee et al., 2000
;
Lisowsky et al., 2001
).
Mitochondrial localization of full-length Alrp is of special interest for
spermatogenesis because it is known that morphological and functional changes
in mitochondria are associated with this highly complex cytodifferentiation
process (Meinhardt et al.,
1999; Russell et al.,
1990
). This was another important reason for investigating the
expression of Alrp during mouse spermatogenesis. Full-length Alrp is
identified as a new intratesticular sulphydryl oxidase that clearly exhibits a
regulated expression pattern and subcellular localization distinct from those
of the Q6-related enzymes. Furthermore, our studies indicate a new function
for mitochondria in the biogenesis of mature sperm cells.
![]() |
Materials and methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
For the analysis of the testis at defined time points after birth, the mouse strain CD1 was used.
Isolation of the testis, separation of cells and fractionation on a 1 % to
3 % bovine serum albumin (BSA) gradient were essentially performed as
described previously (Wolgemuth et al.,
1985) using a CelSep gradient chamber (DuPont). Samples of the
cell fractions were stained with 2 % Toluidine Blue and inspected by oil
immersion microscopy to characterize the cell types. Fractions containing
predominantly the same cell type were pooled: 80-90 % of the cell population
in the pooled fractions was made up of just one cell type.
Antibodies
To raise antibodies in rabbits against human Alrp, a purified
hexahistidinyl-tagged carboxyl-terminal fragment of Alrp (residues 81-205) was
used (Lange et al., 2001;
Lisowsky et al., 2001
).
Antibodies against mouse cyritestin (Chemicon), actin (Oncogene) and
mitochondrial subunit Vb of cytochrome oxidase (Cox Vb) (Molecular Probes)
were purchased from the indicated suppliers or used as described previously
(Linder et al., 1995
). Cy3 and
Cy5 fluorescent secondary antibodies were kindly supplied by Dr H. A.-J.
Müller, Düsseldorf, Germany.
Western blotting
For immunological studies, samples containing approximately 20 µg of
total protein were applied to 4 % to 12 % SDS/polyacrylamide gels
(Novex/Invitrogen). One exception was the separation and identification of
cyritestin. For western blot analysis of this protein, it was essential to use
conventional 10 % polyacrylamide gels according to Laemmli
(1970). Most of the primary
antibodies were detected using alkaline-phosphatase-conjugated secondary
antibodies and chemiluminescence. Cyritestin was identified using
peroxidase-conjugated secondary antibodies and staining.
Immunocytochemistry
For alkaline-phosphatase-aided detection of Erv 1p, tissues were fixed in
paraformaldehyde or ethanol/acetic acid and embedded in Paraplast as described
by Heinlein et al. (1994).
Sections (6 µm) were mounted on SuperFrost slides and dewaxed through
xylene and descending alcohol concentrations, washed in 10 mmol l-1
phosphate buffer, 0.27 mmol l-1 KCl, 140 mmol l-1 NaCl,
0.05 % Tween-20 (PTw) and incubated for 10 min in PTw containing 2 % normal
goat serum (PTwG). Rabbit anti-Erv 1p antiserum was applied at a dilution of
1:50 in PTwG and incubated for 45 min at ambient temperature. The slides were
then washed twice for 10 min in PTw, before the second antibody, goat
anti-rabbit IgG, was added (dilution 1:500) in PTwG; the mixture was incubated
for a further 45 min. Bound alkaline phosphatase activity was monitored by
adding the substrate (0.75 mg ml-1 Nitroblue Tetrazolium and 0.38
mg ml-1 5-bromo-4-chloro-3-indolyl phosphate in alkP reaction
buffer: 100 mmol l-1 Tris-HCl, pH 9.5, 100 mmol l-1
NaCl, 5 mmol l-1 MgCl2). After development of the colour
reaction (5-10 min), the slides were washed in phosphate-buffered saline and
dehydrated. Coverslips were mounted with DePex. For immunofluorescence, Cy3
and Cy5 secondary antibodies were used, and the coverslips were mounted with
Mowiol. Images were collected with a confocal laser scanning microscope and
digitally processed.
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
Comparison of testicular Alrp expression with those of actin,
mitochondrial CoxVb and cytochrome c
Western blots with selected samples from the probes shown in
Fig. 1 were successively probed
with four different antibodies, as listed in
Fig. 2. Again, the antibody
against Alrp identified up to three different forms of this protein. Actin
served as an internal control for protein concentrations. The smaller amount
of actin in some of the samples corresponds with the reduced presence of
cytoskeleton in tissues such as the spleen, lung or blood. The mitochondrial
proteins CoxVb and cytochrome c are markers for the expression status
of proteins from the respiratory chain. Comparison of the expression of CoxVb
and cytochrome c with that of Alrp demonstrates that there is no
correlation between the expression levels of proteins for the respiratory
chain and that for Alrp.
|
Testicular expression of Alrp in postnatal mice from days 13-29
Male mice from the same day of birth were grown for 13 days. Pairs of
animals were then removed from the population and used for the preparation of
whole testis samples. Identical samples from total protein extracts were used
for the immunological studies. The testis-specific marker protein cyritestin
(Heinlein et al., 1994;
Lemaire et al., 1994
;
Linder et al., 1995
) was
included in the analysis together with the actin control. Cyritestin
accumulates during the late stages of sperm differentiation
(Forsbach and Heinlein, 1998
)
and is therefore present at the highest levels around post-natal day 23. In
contrast, Alrp is present at high levels from the very early days of
spermatogensis. High levels of Alrp were also detected on post-natal days 19,
25 and 29 (Fig. 3). This
demonstrates that peaks of Alrp synthesis in the testis are observed
approximately every 6-7 days after birth. This cycle of expression coincides
with the generation of spermatogonia and spermatocytes. These experiments were
repeated three times with different sets of animals. The results were
essentially the same.
|
Analysis of Alrp expression in gradient-separated testis cells
Dissociated testes cells from eight mice were applied to a BSA gradient.
Fractions were collected, and samples were stained and inspected
microscopically. Fractions containing predominantly the same type of cell were
pooled. Samples of these cells were used to prepare total protein extracts for
the immunological studies shown in Fig.
4. The distribution, differentiation-dependent expression and
processing of the germ-cell-specific marker cyritestin served as an internal
control (Forsbach and Heinlein,
1998). Cyritestin is synthesized as a 110 kDa precursor
(Forsbach and Heinlein, 1998
)
and integrated into the membrane of the acrosome
(Linder et al., 1995
). The
intra-acrosomal half of the transmembrane protein is then released, and a 55
kDa fragment is retained in the membrane as the functional protein. The 55 kDa
fragment therefore accumulates during the last stages of sperm cell
maturation. The expression profile for Alrp was different from that of
cyritestin: Alrp was detected in fractions associated with cells
characteristic of the early stages of sperm cell development. The largest
amount of Alrp was found in fractions 51-56, which contain type B
spermatogonia. In fractions containing cells from the last stages of sperm
maturation or in isolated spermatids and spermatozoa, only small amounts of
Alrp were detected. Fractionation experiments were repeated three times with
testis preparations from different animals. The expression analysis for Alrp
gave comparable results in all these experiments.
|
Immunological detection of Alrp in tissue sections
Immunocytochemistry was used to corroborate the results obtained in cell
separation experiments. Paraffin-embedded tissue sections were probed with
anti-Alrp antiserum and chromogenic or fluorescent secondary antibodies. The
signals generated provided additional evidence that Alrp is expressed in
spermatogonia (Figs 5,
6).
|
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Protein analysis of numerous rat and mouse tissues demonstrated that Alrp
is a ubiquitous protein. In accordance with the finding that, under normal
conditions, Alrp is not secreted from cells, blood samples do not contain
Alrp. The very small amount of Alrp that is present in blood samples taken
directly from the liver had probably been released from damaged hepatocytes.
The concentrations of Alrp vary among tissues. Our important new findings are
the high level of Alrp in the brain and cerebellum and the identification of
three different forms of Alrp. Previous studies indicated that different forms
of Alrp may be associated with different localizations and functions
(Gandhi et al., 1999;
Giorda et al., 1996
;
Hofhaus et al., 1999
). During
liver regeneration, there is specific accumulation of a cytosolic 15 kDa Alrp
fragment (Giorda et al., 1996
;
Hagiya et al., 1994
) that may
be associated with its function as a secondary growth factor
(Francavilla et al., 1994
,
Gandhi et al., 1999
;
Wang et al., 1999
).
Our data characterize full-length Alrp as a testicular sulphydryl oxidase
distinct from the Q6-related FAD-dependent rat seminal vesicle sulphydryl
oxidase. The rat Q6 enzyme is a secretory protein found preferentially in
epididymis and seminal vesicles (Benayoun
et al., 2001). In contrast, Alrp is associated with spermatogonia
and early spermatocytes, as verified by the analysis of testis from postnatal
mice of different ages. The distribution of Alrp in gradient fractions of
separated testis cells supports this finding.
Current research suggests that sulphydryl oxidases and other redox proteins
have a broader than expected role in the regulation of cell growth and
differentiation (Eickhoff et al.,
2001; Lisowsky,
2001
). In addition to a defined enzymatic function in modifying
amino acid residues in target proteins, these enzymes also act like cytokines
or growth factors and occur at a variety of subcellular locations
(Benayoun et al., 2001
;
Coppock et al., 1998
;
Eickhoff et al., 2001
;
Hoober and Thorpe, 1999
;
Lee et al., 2000
). One recent
new example is the macrophage migration inhibitory factor MIF. This redox
protein was first described as a classical T-cell cytokine
(Bloom and Bennett, 1966
;
David, 1966
). MIF has since
been identified as a new secretory protein of rat epididymis that is
transferred to spermatozoa and is localized in the outer dense fibres
(Eickhoff et al., 2001
).
Another important example of the synthesis of two isoforms from a nuclear gene
during mouse spermatogenesis has also been described: the alternative splicing
products from the same mouse gene encode mitochondrial transcription factor A
and a testis-specific nuclear HMG box protein whose precise cellular function
is still unknown (Larsson et al.,
1996
).
According to current data, there are two possible functions for Alrp in the
mitochondrial intermembrane space of spermatogonia and spermatocytes. First,
as a sulphydryl oxidase, Alrp could be responsible for the introduction of
specific disulphide bridges into integral mitochondrial membrane proteins, and
changes in the level and activity of Alrp would result in morphological
changes in mitochondria. This would make sense because mitochondria, in
particular, exhibit a highly complicated change in their structure during
spermatogenesis (Meinhardt et al.,
1999). In addition, for the homologous Erv 1p from yeast, we have
shown previously that reduced levels of mitochondrial Erv 1p cause dramatic
changes in the morphology of mitochondria
(Becher et al., 1999
).
Second, Alrp could play a role in the biosynthesis of a product important
for spermatogenesis. Our latest data demonstrate that full-length Alrp is
essential for the biogenesis of cytosolic Fe/S proteins. This could indicate a
specific demand for particular Fe/S-cluster-containing proteins during sperm
development. Recent studies demonstrate that the mitochondria of all
eukaryotes perform a central task in the biogenesis of cellular Fe/S proteins
(for reviews, see Craig et al.,
1999; Lill et al.,
1999
; Lill and Kispal,
2000
). They harbour a complex apparatus, termed the iron/sulphur
cluster (ISC) assembly machinery, consisting of some ten proteins. The ISC
assembly machinery is required for the biogenesis of Fe/S proteins within
mitochondria as well as for the maturation of cytosolic Fe/S proteins
(Kaut et al., 2000
;
Kispal et al., 1999
;
Lange et al., 2000
;
Li et al., 2000
).
Erv1p/Alrp, like the central constituents of the yeast ISC assembly
machinery, is indispensable for life (Lisowsky,
1992,
1996
). Cytosolic and nuclear
Fe/S proteins perform important regulatory functions as enzymes or
transcription factors. The synthesis of Fe/S clusters inside mitochondria is
therefore an essential task independent from the activity of the respiratory
chain. Even under anaerobic conditions, Fe/S clusters have to be synthesized.
Therefore, one does not observe a correlation in the expression levels of
mitochondrial proteins for the respiratory chain and for the Fe/S assembly
machinery. This would also be in accordance with the finding that elevated
levels of mitochondrially localised Alrp in spermatogonia and elongated sperm
cells do not correlate with the levels of expression of mitochondrial CoxVb or
cytochrome c, which are both constituents of the respiratory
chain.
Erv1p/Alrp appears to be the only sulphydryl oxidase detected in the mitochondrial intermembrane space. This opens new lines of investigation for the analysis of sperm development. Future elucidation of the molecular function of Alrp during spermatogenesis will require the identification of sperm proteins harbouring Fe/S clusters whose assembly is dependent on the mitochondrial Fe/S cluster machinery.
![]() |
Acknowledgments |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Becher, D., Kricke, J., Stein, G. and Lisowsky, T. (1999). A mutant for the yeast scERV1 gene displays a new defect in mitochondrial morphology and distribution. Yeast 15,1171 -1181.[Medline]
Benayoun, B., Esnard-Feve, A., Castella, S., Courty, Y. and
Esnard, F. (2001). Rat seminal vesicle FAD-dependent
sulphydryl oxidase. Biochemical characterization and molecular cloning of a
member of the new sulphydryl oxidase/quiescin Q6 gene family. J.
Biol. Chem. 276,13830
-13837.
Bloom, B. R. and Bennett, B. (1966). Mechanism of a reaction in vitro associated with delayed-type hypersensitivity. Science 153,80 -82.[Medline]
Chivers, P. T., Prehoda, K. E. and Raines, R. T. (1997). The CXXC motif: a rheostat in the active site. Biochemistry 36,4061 -4066.[Medline]
Coppock, D. L., Cina-Poppe, D. and Gilleran, S. (1998). The quiescin Q6 gene (QSCN6) is a fusion of two ancient gene families: thioredoxin and ERV1. Genomics 54,460 -468.[Medline]
Craig, E. A., Voisine, C. and Schilke, B. (1999). Mitochondrial iron metabolism in the yeast Saccharomyces cerevisiae. Biol. Chem. 380,1167 -1173.[Medline]
David, J. R. (1966). Delayed hypersensitivity in vitro: its mediation by cellfree substances formed by lymphoid cellantigen interaction. Proc. Natl. Acad. Sci. USA 56,72 -77.[Medline]
Eickhoff, R., Wilhelm, B., Renneberg, H., Wennemuth, G., Bacher, M., Linder, D., Bucala, R., Seitz, J. and Meinhardt, A. (2001). Purification and characterization of macrophage migration inhibitory factor as a secretory protein from rat epididymis: evidence for alternative release and transfer to spermatozoa. Mol. Med. 7,27 -35.[Medline]
Forsbach, A. and Heinlein, U. A. O. (1998).
Intratesticular distribution of cyritestin, a protein involved in gamete
interaction. J. Exp. Biol.
201,861
-867.
Francavilla, A., Hagiya, M., Porter, K. A., Polimeno, L., Ihara, I. and Starzl, T. E. (1994). Augmenter of liver regeneration: its place in the universe of hepatic growth factors. Hepatology 20,747 -757.[Medline]
Gandhi, C. R., Kuddus, R., Subbotin, V. M., Prelich, J., Murase, N., Rao, A. S., Nalesnik, M. A., Watkins, S. C., DeLeo, A., Trucco, M. and Starzl, T. E. (1999). A fresh look at augmenter of liver regeneration in rats. Hepatology 29,1435 -1445.[Medline]
Gerber, J., Muhlenhoff, U., Hofhaus, G., Lill, R. and Lisowsky,
T. (2001). Yeast ERV2p is the first microsomal FAD-linked
sulphydryl oxidase of the Erv1p/Alrp protein family. J. Biol.
Chem. 276,23486
-23491.
Giorda, R., hagiya, M., Seki, T., Shimonishi, M., Sakai, H., Michaelson, J., Francavilla, A., Starzl, T. E. and Trucco, M. (1996). Analysis of the structure and expression of the augmenter of liver regeneration (ALR) gene. Mol. Med. 2, 97-108.[Medline]
Hagiya, M., Francavilla, A., Polimeno, L., Ihara, I., Sakai, H., Seki, T., Shimonishi, M., Porter, K. A. and Starzl, T. E. (1994). Cloning and sequence analysis of the rat augmenter of liver regeneration (ALR) gene: expression of biologically active recombinant ALR and demonstration of tissue distribution. Proc. Natl. Acad. Sci. USA 91,8142 -8146.[Abstract]
Heinlein, U. A. O., Wallat, S., Senftleben, A. and Lemaire, L. (1994). Male germ cell-expressed mouse gene TAZ83 encodes a putative, cysteine-rich transmembrane protein (cyritestin) sharing homologies with snake toxins and spermegg fusion proteins. Dev. Growth Diff. 36,49 -58.
Hofhaus, G., Stein, G., Polimeno, L., Francavilla, A. and Lisowsky, T. (1999). Highly divergent amino termini of the homologous human ALR and yeast scERV1 gene products define species specific differences in cellular localization. Eur. J. Cell Biol. 78,349 -356.[Medline]
Hoober, K. L., Glynn, N. M., Burnside, J., Coppock, D. L. and
Thorpe, C. (1999a). Homology between egg white sulphydryl
oxidase and quiescin Q6 defines a new class of flavin-linked sulphydryl
oxidases. J. Biol. Chem.
274,31759
-31762.
Hoober, K. L., Sheasley, S. L., Gilbert, H. F. and Thorpe,
C. (1999b). Sulphydryl oxidase from egg white. A facile
catalyst for disulphide bond formation in proteins and peptides. J.
Biol. Chem. 274,22147
-22150.
Hoober, K. L. and Thorpe, C. (1999). Egg white sulphydryl oxidase: kinetic mechanism of the catalysis of disulphide bond formation. Biochemistry 38,3211 -3217.[Medline]
Kaut, A., Lange, H., Diekert, K., Kispal, G. and Lill, R.
(2000). Isa1p is a component of the mitochondrial machinery for
maturation of cellular ironsulphur proteins and requires conserved
cysteine residues for function. J. Biol. Chem.
275,15955
-15961.
Kispal, G., Csere, P., Prohl, C. and Lill, R.
(1999). The mitochondrial proteins Atm1p and Nfs1p are essential
for biogenesis of cytosolic Fe/S proteins. EMBO J.
18,3981
-3989.
Kobayashi, T. and Ito, K. (1999). Respiratory
chain strongly oxidizes the CXXC motif of DsbB in the Escherichia
coli disulphide bond formation pathway. EMBO J.
18,1192
-1198.
Laemmli, U. K. (1970). Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227,680 -685.[Medline]
Lange, H., Kaut, A., Kispal, G. and Lill, R.
(2000). A mitochondrial ferredoxin is essential for biogenesis of
cellular ironsulphur proteins. Proc. Natl. Acad. Sci.
USA 97,1050
-1055.
Lange, H., Lisowsky, T., Gerber, J., Muhlenhoff, U., Kispal, G.
and Lill, R. (2001). An essential function of the
mitochondrial sulphydryl oxidase Erv1p/ALR in the maturation of cytosolic Fe/S
proteins. EMBO Rep. 2,715
-720.
Larsson, N. G., Garman, J. D., Oldfors, A., Barsh, G. S. and Clayton, D. A. (1996). A single mouse gene encodes the mitochondrial transcription factor A and a testis-specific nuclear HMG-box protein. Nature Genet. 13,296 -302.[Medline]
Lee, J., Hofhaus, G. and Lisowsky, T. (2000). Erv1p from Saccharomyces cerevisiae is a FAD-linked sulphydryl oxidase. FEBS Lett. 477,62 -66.[Medline]
Lemaire, L., Johnson, K. R., Bammer, S., Petry, P., Ruddle, F. H. and Heinlein, U. A. O. (1994). Chromosomal assignment of three novel mouse genes expressed in testicular cells. Genomics 21,409 -414.[Medline]
Li, Y., Li, M., Xing, G., Hu, Z., Wang, Q., Dong, C., Wei, H.,
Fan, G., Chen, J., Yang, X., Zhao, S., Chen, H., Guan, K., Wu, C., Zhang, C.
and He, F. (2000). Stimulation of the mitogen-activated
protein kinase cascade and tyrosine phosphorylation of the epidermal growth
factor receptor by hepatopoietin. J. Biol. Chem.
275,37443
-37447.
Lill, R., Diekert, K., Kaut, A., Lange, H., Pelzer, W., Prohl, C. and Kispal, G. (1999). The essential role of mitochondria in the biogenesis of cellular ironsulphur proteins. Biol. Chem. 380,1157 -1166.
Lill, R. and Kispal, G. (2000). Maturation of cellular FeS proteins: an essential function of mitochondria. Trends Biochem. Sci. 25,352 -356.[Medline]
Linder, B., Bammer, S. and Heinlein, U. A. O. (1995). Delayed translation and posttranslational processing of cyritestin, an integral transmembrane protein of the mouse acrosome. Exp. Cell Res. 221,66 -72.[Medline]
Lisowsky, T. (1992). Dual function of a new nuclear gene for oxidative phosphorylation and vegetative growth in yeast. Mol. Gen. Genet. 232,58 -64.[Medline]
Lisowsky, T. (1996). Removal of an intron with unique 3' branch site creates an amino-terminal protein sequence directing the scERV1 gene product to mitochondria. Yeast 12,1501 -1510.[Medline]
Lisowsky, T. (2001). Sulphydryl oxidases and the genetics of mitochondrial biogenesis. Rec. Res. Dev. Curr. Genet. 1,1 -10.
Lisowsky, T., Lee, J. E., Polimeno, L., Francavilla, A. and Hofhaus, G. (2001). Mammalian augmenter of liver regeneration protein is a sulphydryl oxidase. Dig. Liver Dis. 33,173 -180.[Medline]
Meinhardt, A., Wilhelm, B. and Seitz, J.
(1999). Expression of mitochondrial marker proteins during
spermatogenesis. Human Reprod. Update
5, 108-119.
Nakamura, H., Nakamura, K. and Yodoi, J. (1997). Redox regulation of cellular activation. Annu. Rev. Immunol. 15,351 -369.[Medline]
Oehmen, F., Aumüller, G., Bergmann, M. and Seitz, J. (1992). Distribution of sulphydryloxidase (SOx) immunoreactivity in the testis of the axolotl (Ambystoma mexicanum) (Amphibia, Urodela). Tissue Cell 23,377 -384.
Polimeno, L., Capuano, F., Marangi, L. C., Margiotta, M., Lisowsky, T., Ierardi, E., Francavilla, R. and Francavilla, A. (2000a). The augmenter of liver regeneration induces mitochondrial gene expression in rat liver and enhances oxidative phosphorylation capacity of liver mitochondria. Dig. Liver Dis. 32,510 -517.[Medline]
Polimeno, L., Lisowsky, T. and Francavilla, A. (1999). From yeast to man from mitochondria to liver regeneration: a new essential gene family. Ital. J. Gastroenterol. Hepatol. 31,494 -500.[Medline]
Polimeno, L., Margiotta, M., Marangi, L., Lisowsky, T., Azzarone, A., Ierardi, E., Frassanito, M. A., Francavilla, R. and Francavilla, A. (2000b). Molecular mechanisms of augmenter of liver regeneration as immunoregulator: its effect on interferon-gamma expression in rat liver. Dig. Liver Dis. 32,217 -225.[Medline]
Russell, L. D., Ettlin, R. A., Sinha Hikim, A. P. and Clegg, E. D. (1990). Histological and Histopathological Evaluation of the Testis. Bolesta, FL: Cache River Press.
Senkevich, T. G., White, C. L., Koonin, E. V. and Moss, B.
(2000). A viral member of the ERV1/ALR protein family
participates in a cytoplasmic pathway of disulphide bond formation.
Proc. Natl. Acad. Sci. USA
97,12068
-12073.
Tanaka, T., Nishiyama, Y., Okada, K., Hirota, K., Matsui, M., Yodoi, J., Hiai, H. and Toyokuni, S. (1997). Induction and nuclear translocation of thioredoxin by oxidative damage in the mouse kidney: independence of tubular necrosis and sulphydryl depletion. Lab. Invest. 77,145 -155.[Medline]
Wang, G., Yang, X., Zhang, Y., Wang, Q., Chen, H., Wei, H.,
Xing, G., Xie, L., Hu, Z., Zhang, C., Fang, D., Wu, C. and He, F.
(1999). Identification and characterization of receptor for
mammalian hepatopoietin that is homologous to yeast ERV1. J. Biol.
Chem. 274,11469
-11472.
Wolgemuth, D. J., Gizang-Ginsberg, E., Engelmyer, E., Gavin, B. J. and Ponzetto, C. (1985). Separation of mouse testis cells on a Celsep (TM) apparatus and their usefulness as a source of high molecular weight DNA or RNA. Gamete Res. 12, 1-10.[Medline]