Identification of novel membrane and secreted proteins upregulated during adipocyte differentiation.
Adipose tissue is the largest organ in the body that secretes soluble proteins such as cytokines. A preadipocyte cell line 3T3-L1 has been widely used for investigations of mechanisms of adipocyte differentiation. 3T3-L1 cells convert to adipocytes in the presence of 1-methyl-3-isobutylxanthine, dexamethasone, and insulin. We screened a cDNA library derived from differentiated 3T3-L1 cells, using the SST-REX method (signal sequence trap by retrovirus-mediated expression screening method). Screening of 4 x 10(5) clones gave rise to 63 known and 8 novel clones. The known clones represented 28 independent proteins, 21 of which were secreted proteins and 7 were membrane proteins. The novel clones represented 7 independent proteins, 5 of which had no similarity to known proteins. Interestingly, most of these novel genes showed differentiation- and tissue-specific expression. The present results indicate that adipocytes specific genes or adipocyte differentiation-related genes encoding membrane and secreted proteins can be readily identified if signal sequence trap screening of differentiated adipocyte-derived cDNAs is done.
Tsuruga
H
H
Department of Hematopoietic Factors, Institute of Medical Science, University of Tokyo, Japan.
Kumagai
H
H
Kojima
T
T
Kitamura
T
T
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution; D015854:Up-Regulation
D018076:DNA, Complementary; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger