title: [Nucleosomal organization of chromatin from sperm of the bivalve mollusk Swiftopecten swifti].
abstract: Composition of basic chromosomal proteins from sperm of the bivalve mollusc Swiftopecten swifti is specific: (1) somatic histone H1 is replaced for a sperm-specific one containing three subfractions, enriched in Arg; (2) low molecular weight sperm-specific basic protein (S protein) is present in the chromatin additionally to the histones. It is shown that chromatin from the mollusc sperm has typical nucleosomal organization, however the DNA repeat length is markedly increased (225 bp) on account of the linker region of the nucleosome. It is found using two-dimensional electrophoresis that fraction of the mononucleosomes is heterogeneous and represented by four electrophoretic subfractions which differ in protein composition and length of DNA they contain. Subfraction which differ in protein composition and length of DNA they contain. Subfractions of mononucleosomes in the order of increase of electrophoretic mobility contain along with core histones: (1)--all H1 subfractions, protein X, protein S; (2)--subfraction H1"', protein X, protein S; (3)--protein S. The particles containing only core histones correspond to the most rapidly migrating band. The data show that protein S is, like histone H1, possibly bound to the linker DNA. Interdependence between the presence of sperm-specific non-core (-linker?) proteins, the increase in size of linker DNA and compaction of sperm chromatin is suggested.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002843:Chromatin / Q000032:analysis*; D004247:DNA / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D006657:Histones / Q000032:analysis; D008297:Male; D008974:Mollusca; D009698:Nucleoproteins / Q000032:analysis*; D009707:Nucleosomes / Q000032:analysis*; D012091:Repetitive Sequences, Nucleic Acid; D013094:Spermatozoa / Q000032:analysis*
chemical_list: D000596:Amino Acids; D002843:Chromatin; D006657:Histones; D009698:Nucleoproteins; D009707:Nucleosomes; D004247:DNA
vernacular_title: Nukleosomnaia organizatsiia khromatine spermiev dvustvorchatogo molliuska Swiftopoecten swifti.