Transient expression of interferon-inducible p204 in the early stage is required for adipogenesis in 3T3-L1 cells.
A member of the interferon-inducible p200 family of proteins, p204, has recently been reported to function in the development of many mesoderm-derived tissues, such as bone, muscle, and cartilage. However, no published study has yet investigated the role of p204 in adipogenesis. Our preliminary experiments showed that p204 can be found in 3T3-L1 preadipocytes, and its expression was up-regulated in a differentiation-dependent manner. As such, we hypothesized that p204 is associated with adipogenesis and focused on the influence of p204 on adipogenesis. In the present study, we investigated the transient elevated expression and cytoplasm-to-nucleus translocation of p204 in the early stage of adipogenesis. To determine the effect of p204 on adipogenesis, p204-siRNA and expression vector were produced for p204 suppression and overexpression, respectively. The knockdown of p204 resulted in a significantly depressed adipocyte differentiation, whereas p204 overexpression promoted adipocyte differentiation. The mRNA expression of adipogenic markers, such as peroxisome-proliferator-activated receptor (PPAR)gamma, CCAAT/enhancer-binding-protein (C/EBP)alpha, lipoprotein lipase, and adipsin, was decreased by p204 suppression and increased by p204 overexpression. A coimmunoprecipitation assay coupled with an indirect immunofluorescence assay also indicated that p204 interacted and colocalized with C/EBPdelta in the nucleus. Furthermore, the knockdown of p204 disrupted the interaction between p204 and C/EBPdelta and partially suppressed the PPARgamma transcriptional activity by dissociating C/EBPdelta with the PPARgamma promoter element. Collectively, our data indicate that the transient expression of p204 in the early stage is indispensable for adipocyte differentiation. Disruption of p204 expression patterns at this stage leads to irreversible damage in fat formation.
Xiao
Jing
J
Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, People's Republic of China.
Sun
Bing
B
Cai
Guo-ping
GP
D041721:3T3-L1 Cells; D050156:Adipogenesis / Q000235:genetics / Q000502:physiology*; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D051743:CCAAT-Enhancer-Binding Protein-delta / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D047369:Chromatin Immunoprecipitation; D011416:Complement Factor D / Q000235:genetics; D019084:Fluorescent Antibody Technique, Indirect; D047468:Immunoprecipitation; D008071:Lipoprotein Lipase / Q000235:genetics; D051379:Mice; D008819:Mice, Nude; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D047495:PPAR gamma / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D034622:RNA Interference; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction
C489664:Ifi16 protein, mouse; D009687:Nuclear Proteins; D047495:PPAR gamma; D010750:Phosphoproteins; D034741:RNA, Small Interfering; D051743:CCAAT-Enhancer-Binding Protein-delta; D008071:Lipoprotein Lipase; D011416:Complement Factor D