title: Chromatin organization during spermiogenesis in Octopus vulgaris. II: DNA-interacting proteins.
abstract: In this article we study the proteins responsible for chromatin condensation during spermiogenesis in the cephalopod Octopus vulgaris. The DNA of ripe sperm nuclei in this species is condensed by a set of five different proteins. Four of these proteins are protamines. The main protamine (Po2), a protein of 44 amino acid residues, is extraordinarily simple (composed of only three different amino acid types: arginine (R), serine (S), and glycine (G). It is a basic molecule consisting of 79.5 mol% arginine residues. The rest of the protamines (Po3, Po4, Po5) are smaller molecules (33, 28, and 30 amino acid residues, respectively) that are homologous among themselves and probably with the main Po2 protamine. The ripe sperm nucleus of O. vulgaris also contains a small quantity of a molecule (Po1) that is similar to Po2 protamine. This protein could represent a Po2 protamine-precursor in a very advanced step of its processing. We discuss the characteristics of these proteins, as well as the relation between the complexity of chromatin condensation and the transitions of nuclear proteins during spermiogenesis in O. vulgaris.
authors.affiliation: Departament Ciencies Fisiològiques II, Facultat Medicina, Universitat Barcelona, Campus Bellvitge, Barcelona, Spain.
authors.forename: Pepita
authors.initials: P
authors.lastname: Giménez-Bonafé
authors.forename: Fina Martínez
authors.initials: FM
authors.lastname: Soler
authors.forename: Carlos
authors.initials: C
authors.lastname: Buesa
authors.forename: Pierre-Eric
authors.initials: PE
authors.lastname: Sautière
authors.forename: Juan
authors.initials: J
authors.lastname: Ausió
authors.forename: Mostafa
authors.initials: M
authors.lastname: Kouach
authors.forename: Harold E
authors.initials: HE
authors.lastname: Kasinsky
authors.forename: Manel
authors.initials: M
authors.lastname: Chiva
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000502:physiology*; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D049831:Octopodiformes / Q000502:physiology*; D011479:Protamines / Q000378:metabolism; D013091:Spermatogenesis / Q000502:physiology*
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011479:Protamines; D004247:DNA