The activation of specific gene transcription in the adipose conversion of 3T3 cells.

During the adipose conversion of 3T3 cells, there occur sequential changes in cellular protein and mRNA composition. To determine if there are also changes in transcription, we have studied the transcripts of specific genes in isolated nuclei prepared before and after adipose conversion. Transcription of three genes encoding adipocyte-specific proteins was detectable only in adipocytes, whereas transcription of actin and collagen type I genes occurred in both adipocytes and preadipocytes. The activation of transcription of adipocyte-specific genes was not synchronous. Thus temporal differences in the appearance of different adipocyte mRNAs probably result from differences in the times of activation of transcription.