Regulation of preadipocyte factor-1 gene expression during 3T3-L1 cell differentiation.
Preadipocyte factor-1 (Pref-1), a novel gene product isolated from murine preadipocyte 3T3-L1 cells, is thought to function as a negative regulator of adipocyte differentiation. We investigated the regulation of Pref-1 expression in 3T3-L1 preadipocytes during proliferation, growth arrest, and early differentiation in the presence and absence of three well described differentiation antagonists: interleukin-11 (IL-11), transforming growth factor-beta, and tumor necrosis factor-alpha. Northern blot analysis was used to determine messenger RNA (mRNA) steady state expression of Pref-1 and two differentiation-specific genes, adipsin and glycerol-3-phosphate dehydrogenase. We confirmed that Pref-1 mRNA is abundant in proliferating preadipocytes and that its expression is dramatically reduced early in differentiation. However, proliferating and growth-arrested cells treated with the differentiation inhibitor IL-11 demonstrated a modest decrease in Pref-1 mRNA abundance. Transforming growth factor-beta and tumor necrosis factor-alpha had little effect. The reduction of Pref-1 mRNA was most dramatic in differentiating preadipocytes treated with IL-11, occurring despite inhibition of adipogenesis, as judged by cell morphology and adipocyte-specific gene expression (adipsin and glycerol-3-phosphate dehydrogenase). This effect of IL-11 on Pref-1 suggests that different mechanisms are responsible for the IL-11-induced and the differentiation- associated down-regulation of Pref-1, thus dissociating Pref-1 regulation from differentiation. We conclude that Pref-1 expression is not a reliable marker of preadipocytes, and that decreased Pref-1 abundance does not function as a trigger for adipocyte differentiation.
Boney
C M
CM
Department of Pediatrics, Brown University, Providence, Rhode Island 02903.
Fiedorek
F T
FT
Paul
S R
SR
Gruppuso
P A
PA
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002135:Calcium-Binding Proteins; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D011416:Complement Factor D; D017931:DNA Primers; D018076:DNA, Complementary; D003907:Dexamethasone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005993:Glycerolphosphate Dehydrogenase / Q000096:biosynthesis; D007328:Insulin / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1 / Q000494:pharmacology; D007700:Kinetics; D008565:Membrane Proteins / Q000096:biosynthesis*; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000096:biosynthesis*; D012697:Serine Endopeptidases / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D002135:Calcium-Binding Proteins; D017931:DNA Primers; D018076:DNA, Complementary; C512925:Dlk1 protein, mouse; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1; D008565:Membrane Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D003907:Dexamethasone; D005993:Glycerolphosphate Dehydrogenase; D012697:Serine Endopeptidases; D011416:Complement Factor D; C493491:complement factor D, mouse; D015056:1-Methyl-3-isobutylxanthine