From the Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720
Received for publication, January 19, 2001, and in revised form, February 12, 2001
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ABSTRACT |
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A 12.5-kDa cysteine-rich adipose tissue-specific
secretory factor (ADSF/resistin) is a novel secreted protein rich in
serine and cysteine residues with a unique cysteine repeat motif of
CX12CX8CXCX3CX10CXCXCX9CC. A single 0.8-kilobase mRNA coding for this protein was found
in various murine white adipose tissues including inguinal and
epididymal fats and also in brown adipose tissue but not in any other
tissues examined. Two species of mRNAs with sizes of 1.4 and 0.8 kilobases were found in rat adipose tissue. Sequence analysis indicates that this is because of two polyadenylation signals, the proximal one
with the sequence AATACA with a single base mismatch from murine AATAAA
and the distal consensus sequence AATAAA. The mRNA level was
markedly increased during 3T3-L1 and primary preadipocyte differentiation into adipocytes. Its expression in adipose tissue is
under tight nutritional and hormonal regulation; the mRNA level was
very low during fasting and increased 25-fold when fasted mice were
refed a high carbohydrate diet. It was also very low in adipose tissue
of streptozotocin-diabetes and increased 23-fold upon insulin
administration. Upon treatment with the conditioned medium from
COS cells transfected with the expression vector, conversion of 3T3-L1
cells to adipocytes was inhibited by 80%. The regulated
expression pattern suggesting this factor as an adipose sensor for the
nutritional state of the animals and the inhibitory effect on adipocyte
differentiation implicate its function as a feedback regulator of adipogenesis.
Adipose tissue is the major energy reservoir in higher eukaryotes;
storing triacylglycerol in periods of energy excess and its
mobilization during energy shortage are its primary purposes. During
adipose tissue development, genes that code for the lipid transport and
lipogenic and lipolytic enzymes are induced to carry out the adipocyte
function of triacylglycerol synthesis, storage, and mobilization. For
the past decades, in vitro systems including preadipocyte
cell lines such as 3T3-L1 cells as well as primary preadipocytes in
culture have been extensively used (1-3). Transcriptional activation
of adipocyte genes has been the focus of much research. CCAAT
enhancer-binding protein
(C/EBP The role of adipose tissue mainly as an organ for energy storage and
mobilization has recently been expanded by the discovery of leptin (10,
11). Leptin is primarily made and secreted by mature adipocytes. It
binds to its receptor in the hypothalamus and may function in
regulating body fat mass (12, 13). Other immune system-related proteins
such as TNF- We report here the identification and function of a
serine/cysteine-rich adipocyte-specific
secretory factor
(ADSF) that does not belong to known
classes of cysteine-rich proteins. Its mRNA is expressed only in
adipose tissue. The mRNA is induced markedly during differentiation
of 3T3-L1 and primary preadipocytes. In fasted or diabetic animals, its
expression is very low or non-detectable in adipose tissue but
increases markedly upon feeding or insulin administration. Furthermore,
when treated with the conditioned medium from COS cells transfected
with the expression vector, adipose conversion of 3T3-L1 cells was
inhibited, indicating its potential role as a feedback regulator of
adipogenesis. During the submission of this manuscript, the Lazar
laboratory (20) reported this protein as a TZD down-regulated factor
contributing to insulin resistance.
Genefilter Microarray Analysis--
Adipose tissue-specific
genes were examined by microarray analysis using rat Genefilter
membranes (Research Genetics). Filters were hybridized with
Animal Treatments--
Mice were fasted for 48 h, or fasted
mice were refed a 58% carbohydrate fat-free diet (21). Induction of
diabetes and insulin treatments were carried out as described
previously (21).
Construction of Plasmids--
A hemagglutinin (HA)-tagged
full-length mouse ADSF/resistin fragment was prepared by PCR
amplification. The 5' primer, 5'-TGGGACAGGAGCTAATACCCAGA-3' and 3'
primer, 5'-GTCAAGCATAATCTGGAACATCATATGGATAGGAAGCGACCTGCAGCTT-3' were used. The resultant PCR product was originally ligated into pCR3.1 (Invitrogen), and a BamHI-XhoI fragment
was then subcloned into pcDNA3.1 (Invitrogen). The sequence of the
resultant plasmid was confirmed by restriction mapping and sequencing.
Differentiation of 3T3-L1 Cells into Adipocytes--
3T3-L1
preadipocytes were maintained in DMEM containing 10% FBS. For
adipocyte differentiation, confluent cells were treated with 1 µM Dex and 0.5 mM MIX as described previously
(22). For experiments in which conditioned medium was used, cells were
cultured in medium composed of 75% conditioned medium and 25% DMEM,
10% FBS plus Dex and MIX.
Preparation of the Stromal Vascular Fraction from Rat Adipose
Tissue and Primary Cell Culture--
The adipose-derived stromal
vascular fractions from rats were prepared as has been described
previously (23). Briefly, the subcutaneous inguinal fat deposits from
female Zuker rats were dissected and the lymph nodes were removed. The
stromal vascular cells were obtained by collagenase (Sigma, 540 units/mg) digestion at 1 mg/ml at 37 °C for 45 min in
Hepes-phosphate buffer (10 mM HEPES, pH 7.4, 135 mM NaCl, 2.2 mM CaCl2, 1.25 mM MgSO4, 0.45 mM
KH2PO4, 2.17 mM
Na2HPO4, 5 mM
D-glucose, and 2% w/v bovine serum albumin). The cell
suspension was filtered through a 100-µm nylon filter and centrifuged
at 400 × g for 10 min. The pellets were washed,
filtered through a 25-µm nylon filter, and plated at a density of
2.5 × 104 cells/cm2 in DMEM, 10% FBS. At
confluence, differentiation was initiated by the addition of 0.1 µM Dex, 0.25 mM MIX, and 17 nM
insulin. After 2 days, the medium was replaced by DMEM, 10% FBS plus
insulin only.
Transient Transfection in COS cells--
The pcDNA3.1
expression vector was transiently transfected into COS cells using
DEAE-dextran in DMEM with 10% serum plus (JRH Biosciences) as
described previously (24). Twenty-four hours after transfection, the
medium was changed to DMEM supplemented with 10% FBS. The conditioned
medium was collected 72 h after transfection, centrifuged at
500 × g for 5 min, and stored at 4 °C for less than
a week before use.
Isolation of RNA and Northern Blot Analysis--
The total RNA
from the rat tissues was prepared by guanidine isothiocyanate/cesium
chloride centrifugation. The total RNA from the cells was prepared
using TriZOL reagent (Life Technologies, Inc.). RNA was electrophoresed
in 1% formaldehyde-agarose gel in 2.2 M formaldehyde, 20 mM MOPS, 1 mM EDTA, and transferred to Hybond N
(Amersham Pharmacia Biotech). After UV cross-linking, the membranes
were hybridized with the Western Blot Analysis--
Cells were lysed in a buffer
containing 50 mM Tris-HCl, pH 8.0, 120 mM NaCl,
0.5% Nonidet P-40, 1 mM EDTA, and 2 mM
phenylmethylsulfonyl fluoride for 30 min on ice. The protein content
was determined by Bradford assay (Bio-Rad). Thirty µg of protein were
subjected to SDS-polyacrylamide gel electrophoresis, electroblotted
onto Immobilon polyvinylidene difluoride membranes (Millipore), and immunodetected using mouse anti-HA antiserum (Covance) and goat anti-mouse IgG-horseradish peroxidase conjugate (Bio-Rad) by using an
enhanced chemiluminescence detection kit (Bio-Rad).
Reverse Transcription Polymerase Chain Reaction
(RT-PCR)--
RNA was reverse transcribed at 37 °C for 60 min, and
the products were used as the template for two PCR reactions in one
tube containing target genes with actin as an internal control. The primers used were PPAR Identification of cDNA Sequence--
To identify novel genes
that are only expressed in adipocytes and are induced during adipocyte
differentiation, we compared expression levels of rat expressed
sequence tag (EST) sequences by cDNA microarray. RNA samples were
prepared from white adipose tissue as well as brown adipose tissue,
liver, muscle, and brain. The RNAs were used to synthesize cDNAs
for hybridization, and those sequences that were expressed only in
white and brown adipose tissues were identified. Candidate EST clones
were sequenced, and one such sequence was identified as that coding for
a novel adipose tissue-specific, serine- and cysteine-rich secreted
protein. This gene was originally named as FIZZ3,
which belongs to a gene family whose founding member, FIZZ1, is
implicated as a possible mediator of neuronal function and airway
hyperactivity (25). While this manuscript was being reviewed, the
protein was also identified as a TZD down-regulated adipocyte protein,
resistin, which may contribute to insulin resistance (20). From now on, we refer to the novel serine/cysteine-rich adipocyte-specific secretory
factor as ADSF/resistin.
The cDNA sequence of rat ADSF/resistin is shown in Fig.
1A. It reveals a 1174-bp
cDNA with two potential polyadenylation signal sequences, the
proximal one at 524 nt and the distal one at 1149 nt. Northern blot
analysis revealed two mRNAs with sizes of 1.4 and 0.8 kb found in
rat adipose tissue with the differences in size attributed to the
3'-untranslated region. In murine fat tissues, on the other hand, we
detected only one mRNA, which corresponds to the shorter rat
mRNA. When we sequenced murine cDNA, we found that unlike the
rat cDNA, the mouse homolog was shorter in the 3'-untranslated
region with only one polyadenylation signal sequence corresponding to
the rat promixal sequence. The mRNA species detected in Northern
blot analysis and sequence analysis indicate that the difference in the
size of rat and murine mRNAs is in the 3'-untranslated region.
Interestingly, mouse cDNA sequence contains a consensus polyadenlylation signal AATAAA. In contrast, rat cDNA sequence reveals the proximal polyadenylation signal AATACA, with a single base
mismatch, which probably is a weak signal and therefore causes the
generation of the longer mRNA using the distal polyadenylation signal of AATAAA. Overall between rat and murine sequences there is
68% homology in nucleotide sequence (85 and 43% in coding and noncoding regions, respectively). The open reading frame encodes a 114 amino acid protein with a calculated molecular mass of 12.5 kDa and
75% homology between the rat and murine sequence (Fig. 1B).
One hydrophobic stretch is predicted by a Kyte-Doolittle plot located
within the first 20 amino-terminal residues and is characteristic of a
signal sequence. To test whether this protein is secreted, we
constructed a HA epitope-tagged expression vector and transiently
transfected it into COS cells. Western blot analysis demonstrated that
the COS cells synthesized a protein with a molecular weight
corresponding to the in vitro synthesized protein, and the
secreted protein was detected in the conditioned medium (Fig. 1C). The most striking structural feature is the presence of
multiple serines and cysteines, each comprising ~10% of the amino
acid residues with a coiled-coil structure. Although there are several classes of cysteine-rich protein motifs, the spacing of the cysteines, CX12CX8CXCX3CX10CXCXCX9CC,
does not match the known classes of cysteine-rich proteins. However,
the cyteine-rich motif predicts possible protein-protein interaction.
Adipose Tissue-specific Expression--
We examined the tissue
distribution of the mRNA by Northern blot analysis using various
tissues from both mice and rats (Fig. 2A). As indicated above, two
mRNA species of 1.4 and 0.8 kb were present only in rat adipose
tissue but not in any other tissues examined including brain, heart,
small intestine, kidney, liver, lung, and skeletal muscle. A single
0.8-kb mRNA was detected only in murine adipose tissue (data not
shown). We also detected the two mRNAs at similar levels in all
regions of rat white adipose tissues including epididymal and inguinal
fat pads. Interestingly, these mRNAs were also found in brown
adipose tissue although in lesser amounts than in white adipose tissue.
We next fractionated adipose tissue into stromal vascular fractions,
which mainly contain preadipocytes and adipocyte fractions. We found
that unlike in adipocyte fractions, these mRNAs were not detectable
in stromal vascular fractions suggesting that ADSF/resistin expression
may be induced during adipogenesis.
Induction of ADSF/Resistin During Adipocyte
Differentiation--
To determine whether ADSF/resistin expression is
regulated during adipocyte differentiation, mRNA levels were
examined in 3T3-L1 preadipocytes during differentiation into adipocytes
(Fig. 2B). The ADSF/resistin mRNA was not detectable in
the preadipocyte stage (Day 0). But levels of the 0.8-kb murine
mRNA, as predicted by the murine origin of 3T3-L1 cells, were
markedly increased during differentiation into adipocytes. As
anticipated, expression of aFABP (aP2) was induced during adipose
conversion, whereas actin expression was decreased by ~50%. We also
carried out in vitro differentiation of stromal vascular
cells isolated from rat adipose tissue. Differentiation of adipose
precursor cells isolated from the epididymal fat pads may better mimic
in vivo processes of adipogenesis. Two species (1.4 and 0.8 kb) of rat mRNAs were undetectable in freshly plated preadipocytes
of stromal vascular fractions, but their expression was increased
dramatically during adipose conversion initiated by Dex and MIX
treatment. The increase in mRNA levels during adipogenesis of both
3T3-L1 and primary preadipocytes was similar to or somewhat later than that of other late adipocyte markers, such as adipocyte fatty acid-binding protein and stearyl CoA reductase. The results of 3T3-L1
and primary preadipocytes in culture along with its tissue distribution
clearly show that the mRNA levels increase during late stages of
adipose tissue development, and therefore ADSF/resistin is expressed
only in adipose tissue in mature rodents.
Nutritional and Insulin Regulation--
To understand the mode of
regulation of ADSF/resistin expression in adipose tissue, we examined
mRNA levels following dietary and hormonal treatments. As shown in
Fig. 3A, the mRNA levels were quite low when mice were fasted. Upon refeeding a high
carbohydrate fat-free diet, the mRNA levels increased 25-fold after
16 h. Likewise, FAS mRNA levels increased by 34-fold with the
same dietary treatment that favors lipogenesis. Nutritional
manipulation of fasting/refeeding causes an increased circulation of
insulin. We tested whether the observed increase in mRNA levels
during fasting/refeeding is caused by an increase in insulin secretion.
We utilized streptozotocin-diabetic mice. The mRNA levels were low
in the adipose tissue of diabetic mice (Fig. 3B). Upon
insulin administration, the mRNA level was increased 23-fold after
30 min. As predicted, FAS mRNA levels increased 15-fold after 30 min. Actin mRNA levels did not change appreciably by
fasting/refeeding or by diabetes/insulin administration. These results
indicate that ADSF/resistin is regulated in a fashion similar to the
lipogenic enzyme, fatty acid synthase. However, unlike the lipogenic
enzymes, which are induced both in liver and adipose tissue during
feeding and by insulin, ADSF/resistin is expressed only in adipose
tissue and induced by nutrition and insulin.
ADSF/Resistin Inhibits Adipocyte Differentiation--
Given that
it is expressed only in adipose tissue and highly induced when the
animals are in a fed state, we predicted that ADSF/resistin might
promote adipoconversion of preadipocytes. Our hypothesis is that this
protein may be a signal to generate adipocytes for the increased
capacity to store excess energy. We collected medium from COS cells
transfected with expression vector containing HA-tagged full-length
mouse cDNA. The conditioned medium was added to differentiating
3T3-L1 cells to test their effect on adipogenesis. 3T3-L1 cells
maintained in conditioned medium collected from COS cells transiently
transfected with control vector differentiated into lipid-laden
adipocytes as shown in oil red O staining (Fig.
4A). Unexpectedly, those cells
maintained in medium from COS cells transfected with HA-tagged
expression vector did not undergo extensive adipose conversion as
judged by lipid staining. Similarly, expression of adipocyte markers, PPAR
Mature adipocytes, the main cellular components of adipose tissue, are
uniquely equipped to function in energy storage and balance under tight
hormonal control. However, with the recent realization that adipocytes
secrete factors known to play a role in appetite control, immune
response, and vascular disease, a much more complex and dynamic role
for adipose tissue has emerged. The best known example is leptin, a
hormone that is primarily made and secreted by mature adipocytes to
regulate adipose fat mass. However, several adipocyte-specific factors
with unknown functions including adipsin, acylation stimulation
protein, and Acrp30/AdipoQ are secreted along with other well
understood factors such as TNF-
INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS AND DISCUSSION
REFERENCES
)1 and PPAR
have
been shown to be critical in directing adipocyte-specific gene
expression and adipogenesis (4-7). In animals, the activities of
critical enzymes in triacylglycerol biosynthesis and lipolysis are
tightly controlled by nutritional and hormonal conditions (8). For
example, feeding causes an induction whereas fasting causes suppression
of lipogenic enzymes. Elevated insulin over a high carbohydrate diet
feeding is thought to induce these enzymes in lipogenesis. The role of
insulin can also be demonstrated by administration of insulin to
diabetic animals. These enzymes have also been shown to be expressed at
a high level in the adipose tissue of animal obesity models including
ob/ob and db/db mice as well as Zucker rats (9). Hyperinsulinemia may
be responsible for elevated levels of the enzymes.
, adipsin, and ACRP30/AdipoQ along with vascular
function-related molecules such as angiotensinogen and plasminogen
activator inhibitor type I have been shown to be secreted by adipose
tissue (14-16). In addition, adipocytes also secrete factors such as
Pref-1, which inhibits adipocyte differentiation (17-19). Although the
precise functions of these molecules are not clear, adipose tissue as a
secretory organ to regulate other physiological processes as well as
energy balance and homeostasis is now well established. Adipose tissue
must secrete factors reflecting the nutritional status and regulating
adipose tissue mass.
EXPERIMENTAL PROCEDURES
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS AND DISCUSSION
REFERENCES
-33P-labeled cDNAs synthesized with 5 µg of total
RNA. Spots exclusively hybridized with cDNA probes prepared from
adipose tissue RNA were used for sequence analysis.
-32P-labeled cDNA
probes in ExpressHyb solution (CLONTECH). The
membranes were exposed to x-ray film with an intensifying screen, and
the signals were scanned using the Molecular Analyst (Bio-Rad).
(PCR product of 375 bp in length),
5'-ATGCCATTCTGGCCCACCAAC-3' and 5'-CCTTGCATCCTTCCAAAGCAT-3'; aFABP (PCR
product of 310 bp in length) 5'-CTTGTCTCCAGTGAAAACTT-3' and
5'-ACCTTCTCGTTTTCTTTAT-3'; FAS (PCR product of 120 bp in length),
5'-AGGGGTCGACCTGGTCCTCA-3' and 5'-GGGTGGTTGTTAGAAAGAT-3'; and actin
(PCR product of 282 bp in length), 5'-TCCTATGTGGGTGACGAGGC-3' and
5'-CATGGCTGGGGTGTTGAAGG-3'.
RESULTS AND DISCUSSION
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS AND DISCUSSION
REFERENCES
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Fig. 1.
Comparison of structure between mouse and rat
ADSF/resistin and its expression. A, coding sequences
are capitalized. Lines indicate identical
residues, and the possible polyadenylation signals are
boxed. Full and partial corresponding nucleotide sequences
are in the TIGR database under the following tentative consensus
sequence numbers; mouse DNA sequence, TC148909 and rat DNA sequence,
TC119941, respectively. B, an alignment of the predicted
amino acids from mouse and rat using the ClustalW program is shown.
C, Northern blot analysis of rat and mouse mRNAs in
adult white adipose tissues. Ten µg of total RNA from the white
adipose tissue of 8-week-old male rats (lane 1) and mice
(lane 2) were subjected to Northern blot analysis. Positions
of 28 S and 18 S ribosomal RNA are shown. Cell lysates and conditioned
medium from COS cells transiently transfected with HA-tagged murine
expression vector or an empty vector were subjected to Western blot
analysis. Lane 1, lysate from control vector transfected
cells; lane 2, lysate from cells transfected with HA-tagged
expression vector; lane 3, conditioned medium collected from
cells transfected with the expression vector.
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Fig. 2.
ADSF/resistin mRNA expression in adult
rat tissues and its expression during adipocyte differentiation.
A, Ten µg of total RNA from various rat tissues were
subjected to 1% agarose gels and hybridized to 32P-labeled
cDNA. SI and SM designate small intestine and skeletal muscle,
respectively. Ten µg of total RNA from brown fat (BAT),
epididymal fat (Epi.), and inguinal fat (Ing.)
pads of adult rats, and from stromal vascular fractions
(SVF), and mature adipocyte fractions (Ad.F) of
rat inguinal fat pads were used for Northern blot analysis. Positions
of 28 S and 18 S ribosomal RNA from ethidium bromide-stained gels are
shown. B, Five µg of RNA prepared from cells at the
indicated time points of 0 (at confluence), day 1, day 3, day 4, and
day 6 were subjected to Northern blot analysis for ADSF/resistin,
aFABP, SCD, and PPAR . C, Two different preparations of
stromal vascular fractions from fat pads were subjected to in
vitro adipocyte differentiation. RNA prepared from cells at the
indicated time points of 0 (at confluence), day 0.5, day 2.5, and day 9 were subjected to Northern blot analysis for ADSF/resistin, aFABP, SCD,
and PPAR
.
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Fig. 3.
Nutritional and hormonal regulation of
ADSF/resistin mRNA expression in mice. A, total RNA
prepared from adipose tissue of mice fasted for 48 h, or refed a
high carbohydrate diet was used for Northern blot analysis.
B, total RNA isolated from the white adipose tissue of
streptozotocin-diabetic mice and of streptozotocin-diabetic mice
treated with insulin was used for Northern blot analysis for
ADSF/resistin, FAS, and actin mRNAs. 28 S and 18 S ribosomal RNA
from ethidium bromide-stained gels are shown.
, aFABP, and fatty acid synthase was decreased by 80% when cells were treated with conditioned medium from COS cells transfected with HA-tagged expression vector (Fig. 4B). The actin
mRNA level of these cells was somewhat higher, as expected. These
results clearly demonstrate an inhibitory effect of ADSF/resistin on
adipose conversion.
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Fig. 4.
Conditioned medium from COS cells transfected
with HA-tagged murine ADSF/resistin expression vector inhibits 3T3-L1
adipocyte differentiation. 3T3-L1 cells were differentiated in
conditioned medium from COS cells transfected with pcDNA3.1 control
vector and expression vector containing HA-tagged mouse cDNA
sequence as described under "Experimental Procedures."
A, 3T3-L1 cells differentiated in serum-containing
conditioned medium from COS cells transfected with empty vector
(lane 1) or HA-tagged expression vector (lane 2)
were stained by oil red O. B, RT-PCR analysis for adipocyte
markers (PPAR , FAS, aFABP, and actin) after differentiation.
, angiotensinogen, and plasminogen
activator inhibitor type-I. Most of these factors appear to be related
to immune or vascular functions. These examples clearly establish that
the adipocytes behave as endocrine as well as paracrine/autocrine cells. The exact role of the ADSF/resistin secreted from adipose tissue
is not yet known. It is composed of cysteine-rich domain with unique
cysteine spacing and may potentially participate in protein-protein
interaction. It is exclusively made in adipose tissue and is secreted
to the medium. Its exclusive expression in adipocytes, its large
increase during the late stage of adipogenesis, and its dramatic
induction during fasting/refeeding and by insulin administration to
streptozotocin-diabetic animals suggest that this factor may be
involved in sensing the nutritional status of the animals to affect
adipogenesis. Some of these properties are most similar to those
observed with leptin, which is secreted only by adipocytes and is
induced dramatically by fasting/refeeding and by diabetes/insulin. We
speculate that this factor may be a molecule that serves as a feedback
signal to restrict adipose tissue formation. It is also possible that
it functions in an opposite manner to known differentiation agents such
as Dex, MIX, and insulin during adipocyte differentiation The recent
report of ADSF/resistin as a TZD down-regulated adipose tissue factor, which may antagonize insulin action by linking obesity to diabetes, is
also intriguing and needs further study.
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FOOTNOTES |
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* This work was supported by National Institutes of Health Grant DK50828 (to H. S. S.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
To whom correspondence should be addressed. Tel.: 510-642-3978;
Fax: 510-642-0535; E-mail: hsul@nature.berkeley.edu.
Published, JBC Papers in Press, February 15, 2001, DOI 10.1074/jbc.C100028200
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ABBREVIATIONS |
---|
The abbreviations used are:
C/EBP, CCAAT
enhancer-binding protein
;
ADSF, adipose tissue-specific secretory
factor;
Pref-1, preadipocyte factor-1;
FBS, fetal bovine serum;
Dex, dexamethasone;
MIX, methylisobutylxanthine;
FAS, fatty acid synthase;
PPAR
, peroxisome proliferator-activated receptor
;
aFABP, adipocyte fatty acid-binding protein;
SCD, stearoyl CoA desaturase;
DMEM, Dulbecco's modified Eagle's medium;
TZD, thiazolidinediones;
bp, base pairs;
nt, nucleotide;
HA, hemagglutinin;
PCR, polymerase
chain reaction;
RT-PCR, reverse transcriptase PCR;
EST, expressed
sequence tag.
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REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() |
---|
1. |
Gregoire, F. M.,
Smas, C. M.,
and Sul, H. S.
(1998)
Physiol. Rev.
78,
783-809 |
2. | Green, H., and Kehinde, O. (1976) Cell 7, 105-113[Medline] [Order article via Infotrieve] |
3. | Wienderer, L., and Loffler, G. (1987) J. Lipid Res. 28, 649-658[Abstract] |
4. | Christy, R. J., Yang, V. W., Ntambi, J. M., Geiman, D. E., Landschulz, W. H., Friedman, A. D., Nakabeppu, Y., Kelly, T. J., and Lane, M. D. (1989) Genes Dev. 3, 1323-1335[Abstract] |
5. | Umek, R. M. F, Friedman, A. D., and McKnight, S. L. (1991) Science 251, 288-292[Medline] [Order article via Infotrieve] |
6. | Tontonoz, P. E., Hu, E., Graves, R. A., Budavari, A. I., and Spiegelman, B. M. (1994) Genes Dev. 8, 1224-1234[Abstract] |
7. | Brun, R. P., Tontonoz, P., Forman, B. M., Ellis, R., Chen, J., Evans, R. M., and Spiegelman, B. M. (1996) Genes Dev. 10, 974-984[Abstract] |
8. |
Joseph, D.,
Paulauskis, J. D.,
and Sul, H. S.
(1989)
J. Biol. Chem.
264,
574-577 |
9. | Penicaud, L., Ferre, P., Assimacopoulos-Jeannet, F., Perdereau, D., Leturque, A., Jeanrenaud, B., Picon, L., and Girard, J. (1991) Biochem. J. 279, 303-308[Medline] [Order article via Infotrieve] |
10. | Zhang, Y., Proenca, R., Maffei, M., Barone, M., Leopold, L., and Friedman, J. M. (1994) Nature 372, 425-432[CrossRef][Medline] [Order article via Infotrieve] |
11. | Halaas, J. L., Gajiwala, K. S., Maffei, M., Cohen, S. L., Chait, B. T., Rabinowitz, D., Lallone, R. L., Burley, S. K., and Friedman, J. M. (1995) Science 269, 543-546[Medline] [Order article via Infotrieve] |
12. | Maffei, M., Fei, H., Lee, G. H., Dani, C., Leroy, P., Zhang, Y., Proenca, R., Negrel, R., Ailhaud, G., and Friedman, J. M. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 6957-6960[Abstract] |
13. | Hotamisligil, G. S., and Spiegelman, B. M. (1996) Science 271, 665-668[Abstract] |
14. |
Scherer, P. E.,
Williams, S.,
Fogliano, M.,
Baldini, G.,
and Lodish, H. F.
(1995)
J. Biol. Chem.
270,
26746-26749 |
15. |
He, E.,
Liang, P.,
and Spiegelman, B. M.
(1996)
J. Biol. Chem.
271,
10697-10703 |
16. | Shimomura, L. T., Funahashi, M., Takahashi, K., Maeda, K., Kotani, T., Nakamura, S., Yamashita, M., Miura, Y., Fukuda, K., Takemura, K., Tokunaga, K., and Matsuzawa, Y. (1996) Nat. Med. 2, 800-803[Medline] [Order article via Infotrieve] |
17. | Smas, C. M., Chen, L., and Sul, H. S. (1997) Mol. Cell. Biol. 17, 977-988[Abstract] |
18. | Smas, C. M., and Sul, H. S. (1993) Cell 73, 725-734[Medline] [Order article via Infotrieve] |
19. |
Smas, C. M.,
Kachinskas, D.,
Liu, C.-M.,
Xie, X.,
Dircks, L. K.,
and Sul, H. S.
(1998)
J. Biol. Chem.
273,
31751-31758 |
20. | Steppan, C. M., Balley, S. T., Bhat, S., Brown, E. J., Banerjee, R. R., Wright, C. M., Patel, H. R., Ahima, R. S., and Lazar, M. A. (2001) Nature 409, 307-312[CrossRef][Medline] [Order article via Infotrieve] |
21. |
Moon, Y. S.,
Latasa, M. J.,
Kim, K.-H.,
Wang, D.,
and Sul, H. S.
(2000)
J. Biol. Chem.
275,
10121-10127 |
22. | Rubin, C. S., Hirsch, A., Fung, C., and Rosen, O. M. (1978) J. Biol. Chem. 253, 7570-7578[Medline] [Order article via Infotrieve] |
23. | Gregoire, F. M., Johnson, P. R., and Greenwood, M. R. (1995) Int. J. Obes. Relat. Metab. Disord. 19, 664-670[Medline] [Order article via Infotrieve] |
24. | Gulick, T. (1996) in Current Protocols in Molecular Biology (Ausubel, F. M. , Brent, R. , Kingston, R. E. , Moore, D. D. , Seidman, J. G. , Smith, J. A. , and Struhl, K., eds) , pp. 9201-9210, John Wiley & Sons, Inc., New York |
25. |
Holcomb, I. N.,
Kabakoff, R. C.,
Chan, B.,
Baker, T. W.,
Gurney, A.,
Henzel, W.,
Nelson, C.,
Lowman, H. B.,
Wright, B. D.,
Skelton, N. J.,
Frantz, G. D.,
Tumas, D. B,
Peale, F. V.,
Shelton, D. L.,
and Hebert, C. C.
(2000)
EMBO J.
19,
4046-4055 |