title: Genomic and proteomic dissection and characterization of the human sperm chromatin.
abstract: The mammalian spermatozoon has a unique chromatin structure where the majority of DNA is packaged by protamines, while a small fraction (∼8%) remains associated with nucleosomes. However, the chromatin affinity and repertoire of the additional proteins constituting the different sperm chromatin fractions have not yet been explored. To address this we have carried out a genomic and proteomic characterization of human sperm samples subjected to chromatin fractionation using either 0.65 M NaCl extraction followed by EcoRI/BamHI DNA restriction enzyme digestion, or micrococcal nuclease digestion. DNA fractions corresponding to the nucleosome-packaged DNA were sequenced, confirming an appropriate dissection of the sperm chromatin. In addition we detected and sequenced a subnucleosomal particle. Although both fractions were highly enriched at gene promoters, some sequences were found to be exclusively associated with one of those. The results of the proteomic analyses demonstrate that there are two distinct sets of sperm proteins which differ in chromatin affinity. Histone variants, transcription factors, chromatin-associated and modifying proteins involved in regulatory roles were identified as weakly attached to the sperm DNA, whereas proteins with structural roles were identified in the condensed fraction. Many factors, such as the histone lysine demethylase PHF8 identified for the first time in the human sperm cell in this study, were identified exclusively in soluble fraction. Our results provide additional support to the possibility that all of these factors may constitute additional layers of sperm epigenetic information or have structural or regulatory roles transmitted by the sperm cell to the oocyte at fertilization.
authors.affiliation: Human Genetics Research Group, IDIBAPS, Faculty of Medicine, University of Barcelona, Casanova 143, 08036 Barcelona, Spain Biochemistry and Molecular Genetics Service, Biomedical Diagnostic Centre, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain.
authors.forename: Judit
authors.initials: J
authors.lastname: Castillo
authors.affiliation: Human Genetics Research Group, IDIBAPS, Faculty of Medicine, University of Barcelona, Casanova 143, 08036 Barcelona, Spain Biochemistry and Molecular Genetics Service, Biomedical Diagnostic Centre, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain Biology of Reproduction and Stem Cell Group, Centre for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Amaral
authors.affiliation: Human Genetics Research Group, IDIBAPS, Faculty of Medicine, University of Barcelona, Casanova 143, 08036 Barcelona, Spain Biochemistry and Molecular Genetics Service, Biomedical Diagnostic Centre, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain.
authors.forename: Rubén
authors.initials: R
authors.lastname: Azpiazu
authors.affiliation: Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain.
authors.forename: Tanya
authors.initials: T
authors.lastname: Vavouri
authors.affiliation: Proteomics Unit, Scientific and Technological Centres of the University of Barcelona (CCiTUB), Casanova 143, 08036 Barcelona, Spain.
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Estanyol
authors.affiliation: Clinic Institute of Gynaecology, Obstetrics and Neonatology, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain.
authors.forename: Josep Lluis
authors.initials: JL
authors.lastname: Ballescà
authors.affiliation: Human Genetics Research Group, IDIBAPS, Faculty of Medicine, University of Barcelona, Casanova 143, 08036 Barcelona, Spain Biochemistry and Molecular Genetics Service, Biomedical Diagnostic Centre, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain roliva@ub.edu.
authors.forename: Rafael
authors.initials: R
authors.lastname: Oliva
mesh_terms: D002843:Chromatin / Q000737:chemistry / Q000378:metabolism*; D044127:Epigenesis, Genetic; D023281:Genomics; D056466:Histone Demethylases / Q000032:analysis / Q000378:metabolism; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008297:Male; D040901:Proteomics; D013094:Spermatozoa / Q000378:metabolism*; D014157:Transcription Factors / Q000032:analysis / Q000378:metabolism
chemical_list: D002843:Chromatin; D006657:Histones; D014157:Transcription Factors; D056466:Histone Demethylases; C511934:PHF8 protein, human
keywords: chromatin; epigenetics; genomics; proteomics; sperm