title: New insights into protamine-like component organization in Mytilus galloprovincialis' sperm chromatin.
abstract: We have analyzed Mytilus galloprovincialis' sperm chromatin, which consists of three protamine-like proteins, PL-II, PL-III, and PL-IV, in addition to a residual amount of the four core histones. We have probed the structure of this sperm chromatin through digestion with micrococcal nuclease (MNase) in combination with salt fractionation. Furthermore, we used the electrophoretic mobility shift assay to define DNA-binding mode of PL-II and PL-III and turbidimetric assays to determine their self-association ability in the presence of sodium phosphate. Although in literature it is reported that M. galloprovincialis' sperm chromatin lacks nucleosomal organization, our results obtained by MNase digestion suggest the existence of a likely unusual organization, in which there would be a more accessible location of PL-II/PL-IV when compared with PL-III and core histones. So, we hypothesize that in M. galloprovincialis' sperm chromatin organization DNA is wrapped around a PL-III protein core and core histones and PL-II and PL-IV are bound to the flanking DNA regions (similarly to somatic histone H1). Furthermore, we propose that PL's K/R ratio affects their DNA-binding mode and self-association ability as reported previously for somatic and sperm H1 histones.
authors.affiliation: 1 Department of Biology, University of Naples Federico II , Naples, Italy .
authors.forename: Quirino Attilio
authors.initials: QA
authors.lastname: Vassalli
authors.forename: Filomena
authors.initials: F
authors.lastname: Caccavale
authors.forename: Stefano
authors.initials: S
authors.lastname: Avagnano
authors.forename: Alessandra
authors.initials: A
authors.lastname: Murolo
authors.forename: Giulia
authors.initials: G
authors.lastname: Guerriero
authors.forename: Laura
authors.initials: L
authors.lastname: Fucci
authors.forename: Juan
authors.initials: J
authors.lastname: Ausió
authors.forename: Marina
authors.initials: M
authors.lastname: Piscopo
mesh_terms: D000818:Animals; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D006657:Histones / Q000378:metabolism; D008297:Male; D008836:Micrococcal Nuclease / Q000378:metabolism; D049878:Mytilus / Q000235:genetics / Q000378:metabolism*; D011479:Protamines / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000302:isolation & purification / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D002843:Chromatin; D006657:Histones; D011479:Protamines; D020033:Protein Isoforms; C093295:protamine-like protein III; D004247:DNA; D008836:Micrococcal Nuclease