Protein-DNA interactions associated with the onset of testis-specific expression of the mammalian Pgk-2 gene.
We have identified difference in protein-DNA interactions associated with the promoter of the mammalian spermatogenesis-specific Pgk-2 gene in expressing and nonexpressing cells, using a band shift assay. We compared DNA-binding activities in nuclear protein extracts from expressing adult testis cells versus nonexpressing prepuberal testis cells and nonexpressing somatic cells. One or two DNA-binding activities were found to be uniquely associated with the expressed state of Pgk-2, while a third appears to be associated with the nonexpressed state. All three of these activities map to a region within the first 40 bp upstream from the core promoter of this gene. The Pgk-2 core promoter lacks a TATA box but contain a GC box and a CAAT box. We show that the GC box binds the ubiquitous transcription factor Sp1 and that the CAAT box binds CTF-1, both of which are present in extracts from all three tissue types tested. These results suggest that tissue-specific transcription of the Pgk-2 gene is associated with changes in protein-DNA interactions occurring within a 40-bp enhancer region and that different arrays of protein-DNA interactions in this region are associated with the actively expressed state of the Pgk-2 gene in spermatocytes and spermatids and with the terminally repressed state of Pgk-2 in somatic cells.
Gebara
M M
MM
Division of Reproductive Biology, Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland 21205.
McCarrey
J R
JR
D000818:Animals; D001483:Base Sequence; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010735:Phosphoglycerate Kinase / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D012741:Sexual Maturation / Q000502:physiology*; D016329:Sp1 Transcription Factor / Q000235:genetics; D013737:Testis / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D010735:Phosphoglycerate Kinase