In vivo analysis of developmentally and evolutionarily dynamic protein-DNA interactions regulating transcription of the Pgk2 gene during mammalian spermatogenesis.
Transcription of the testis-specific Pgk2 gene is selectively activated in primary spermatocytes to provide a source of phosphoglycerate kinase that is critical to normal motility and fertility of mammalian spermatozoa. We examined dynamic changes in protein-DNA interactions at the Pgk2 gene promoter during murine spermatogenesis in vivo by performing genomic footprinting and chromatin immunoprecipitation assays with enriched populations of murine spermatogenic cells at stages prior to, during, and following transcription of this gene. We found that genes encoding the testis-specific homeodomain factor PBX4 and its coactivator, PREP1, are expressed in patterns that mirror expression of the Pgk2 gene and that these factors become bound to the Pgk2 enhancer in cells in which this gene is actively expressed. We therefore suggest that these factors, along with CREM and SP3, direct stage- and cell type-specific transcription of the Pgk2 gene during spermatogenesis. We propose that binding of PBX4, plus its coactivator PREP1, is a rate-limiting step leading to the initiation of tissue-specific transcription of the Pgk2 gene. This study provides insight into the developmentally dynamic establishment of tissue-specific protein-DNA interactions in vivo. It also allows us to speculate about the events that led to tissue-specific regulation of the Pgk2 gene during mammalian evolution.
Yoshioka
Hirotaka
H
Department of Biology, University of Texas at San Antonio, San Antonio, Texas 78249, USA.
Geyer
Christopher B
CB
Hornecker
Jacey L
JL
Patel
Krishan T
KT
McCarrey
John R
JR
D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010735:Phosphoglycerate Kinase; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D013091:Spermatogenesis / Q000502:physiology*; D013154:Spleen / Q000166:cytology / Q000502:physiology; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D007527:Isoenzymes; C432153:Pbx4 protein, mouse; C491412:Pknox1 protein, mouse; D010735:Phosphoglycerate Kinase; C104317:phosphoglycerate kinase, testis specific