IBYME   02675
INSTITUTO DE BIOLOGIA Y MEDICINA EXPERIMENTAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Impact of the genetic background on the reproductive phenotype of crisp1 and crisp4 knockout mice
Autor/es:
PATRICIA S. CUASNICÚ; MARIA A. BATTISTONE; MARIANA WEIGEL MUÑOZ; VANINA G DA ROS; NICOLAS G. BRUKMAN; OMAR PIGNATARO; GUILLERMO CARVAJAL
Reunión:
Congreso; Gordon Research Conference; 2017
Resumen:
Epididymal CRISP1 and CRISP4 associate with sperm during maturation and participate in fertilization very likely through their ability to regulate critical sperm Ca2+ channels such as CatSper and TRPM8. In spite of this, CRISP1 and CRISP4 knockout (KO) mice are fertile. As it has been reported that a single mutation can produce markedly different phenotypes depending on the genetic background of the animals, in the present work we studied the effect of the genetic background on the reproductive phenotype of CRISP1 and CRISP4 KO mice. The new CRISP1 and CRISP4 KO colonies used in this study had a homogeneous C57BL6 background (generated by backcrossing the original 129SvEv/C57BL6N mice), and a mixed C57BL6/DBA background, respectively. Fertility was evaluated by mating, total motility by CASA, tyrosine phosphorylation (pTyR) by Western blot, cAMP levels by RIA, intracellular Ca2+ levels by flow cytometry, and fertilizing ability by IVF. Results revealed that males from CRISP1 and CRISP4 KO colonies remained fertile but their sperm exhibited changes in several parameters compared to those observed for the original colonies. Differently from CRISP1 KO sperm from the mixed genetic background which had shown a clear reduced pTyR, CRISP1 KO sperm from the homogeneous colony had normal pTyR but significantly reduced sperm motility. Interestingly, both reduced pTyR and motility could be restored by exposure of sperm to dbcAMP+IBMX, suggesting a deficiency in cAMP levels in cells from the two genetic backgrounds. Subsequent studies confirmed the presence of lower cAMP levels in both groups, indicating that the same cAMP defect could be manifested in two different ways depending on the genetic background of the animal. In the case of CRISP4, differently from what had been reported in C57BL6N, sperm from the new mixed C57BL6/DBA colony showed significantly lower pTyR levels, normal sperm-ZP binding, and lower fusion ability than wild type sperm. These sperm also showed a lower increase in intracellular Ca2+ during capacitation and responded differentially to Ca2+ ionophore than controls. Altogether, our results indicate that the phenotypes of CRISP1 and CRISP4 KO mice are not entirely controlled by the mutation at Crisp1 or Crisp4 loci but are influenced by the genetic background of the animal. Considering the wide range of genetic backgrounds inherent to humans, these results highlight the relevance of analyzing the phenotype of a particular mutation in different inbred strains to improve the diagnosis and treatment of human infertility