title: Possible participation of calmodulin in the decondensation of nuclei isolated from guinea pig spermatozoa.
abstract: The guinea pig spermatozoid nucleus contains actin, myosin, spectrin and cytokeratin. Also, it has been reported that phalloidin and/or 2,3-butanedione monoxime retard the sperm nuclear decondensation caused by heparin, suggesting a role for F-actin and myosin in nuclear stability. The presence of an F-actin/myosin dynamic system in these nuclei led us to search for proteins usually related to this system. In guinea pig sperm nuclei we detected calmodulin, F-actin, the myosin light chain and an actin-myosin complex. To define whether calmodulin participates in nuclear-dynamics, the effect of the calmodulin antagonists W5, W7 and calmidazolium was tested on the decondensation of nuclei promoted by either heparin or by a Xenopus laevis egg extract. All antagonists inhibited both the heparin- and the X. laevis egg extract-mediated nuclear decondensation. Heparin-mediated decondensation was faster and led to loss of nuclei. The X. laevis egg extract-promoted decondensation was slower and did not result in loss of the decondensed nuclei. It is suggested that in guinea pig sperm calmodulin participates in the nuclear decondensation process.
authors: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), PC 07360, México, D. F., México.
authors: Armando
authors: A
authors: Zepeda-Bastida
authors: Natalia
authors: N
authors: Chiquete-Felix
authors: Juan
authors: J
authors: Ocampo-López
authors: Salvador
authors: S
authors: Uribe-Carvajal
authors: Adela
authors: A
authors: Mújica
mesh_terms: D000818:Animals; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D006168:Guinea Pigs; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D002147:Calmodulin; D007093:Imidazoles; C031938:calmidazolium