Differential expression of the adipocyte amino acid transporter is transactivated by SP1 and SP3 during the 3T3-L1 preadipocyte differentiation process.
It was identified that a Sp1-like cis-element in the adipocyte amino acid transporter gene (AAAT) promoter is the major cis-motif for its induced expression during the 3T3-L1 preadipocyte differentiation process. Electrophoretic mobility shift analysis of this cis DNA element showed that the transcription factors binding to this sequence were Sp1 and Sp3. Protein analysis of Sp1 and Sp3 in nuclear extracts from 3T3-L1 cells at various differentiation stages indicated that these two transcription factors existed in noninduced 3T3-L1 preadipocytes, but they did not bind to the AAAT promoter element with high affinity. They were activated after differentiation induction. It was further demonstrated that dephosphorylation of Sp1 increased its binding affinity to this inducible AAAT promoter element.
Zhu
Q
Q
Shanghai Life Sciences Research Center, Chinese Academy of Sciences, Shanghai, 200031, China.
Liao
K
K
D016475:3T3 Cells; D017667:Adipocytes / Q000378:metabolism*; D026905:Amino Acid Transport Systems; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000502:physiology*; D051379:Mice; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D016329:Sp1 Transcription Factor / Q000502:physiology*; D051705:Sp3 Transcription Factor; D013234:Stem Cells / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000502:physiology*
D026905:Amino Acid Transport Systems; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D016329:Sp1 Transcription Factor; C497122:Sp3 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D051705:Sp3 Transcription Factor