Transcription and promoter usage of the myc gene in normal somatic and spermatogenic cells

In somatic cells the level of myc transcription is not restricted to particular cell types but correlates closely with the rate of cell division. Such transcription involves the use of two active myc promoters and produces two messenger RNA species that are differentially represented among the transcripts of different tissues. In apparent contrast to somatic cells, mitotically and meiotically dividing germ cells have veryfew myc transcripts and appear to proliferate, at least for a few divisions, in the absence of myc transcription. These results raise interesting questions regarding the role of the myc gene product in terminally differentiating cells, particularly of the germ line series.