title: Mutually exclusive interaction of the CCAAT-binding factor and of a displacement protein with overlapping sequences of a histone gene promoter.
abstract: The sperm histone H2B-1 gene of the sea urchin Psammechinus miliaris contains two octamer sequences (ATTTGCAT) and two CCAAT motifs upstream of its TATA box. The CCAAT-binding factors present in nuclear extracts from testis and from blastula and gastrula embryos are indistinguishable by mobility shift and methylation interference analysis. However, there is a testis-specific octamer-binding factor in addition to the ubiquitous form. In DNAase I protection experiments, the CCAAT-binding factor of only the testis extract is able to interact with the sperm H2B promoter. In the two embryonic extracts a novel factor binds with high affinity to sequences overlapping the proximal CCAAT element, thus preventing the DNA interaction of the CCAAT-binding factor in the embryo where the sperm H2B gene is not expressed. This CCAAT displacement protein may therefore act as a repressor of sperm H2B gene transcription.
mesh_terms: D001483:Base Sequence; D004625:Embryo, Nonmammalian; D005786:Gene Expression Regulation; D006657:Histones / Q000235:genetics*; D008297:Male; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012617:Sea Urchins; D013094:Spermatozoa / Q000648:ultrastructure; D013737:Testis / Q000648:ultrastructure; D014158:Transcription, Genetic
chemical_list: D006657:Histones