Résumé
14-3-3e and 14-3-3c localize to the centrosome and regulate centrosome duplication, by inhibiting cdc25C function. As14-3-3c and 14-3-3e form a complex with centrosomal proteins, we asked if this ability was required to regulate centrosomeduplication. The results in this report demonstrate that 14-3-3e and 14-3-3c form a complex with Centrin2 and that thebinding site is located in the N-terminal EF hand in Centrin2, EF1. A Centrin2 mutant that does not form a complex with14-3-3 proteins displays a punctate cytoplasmic localization and does not localize to the centrosome. These results suggestthat in addition to negatively regulating centrosome duplication as previously reported, 14-3-3 proteins might also berequired for centriole biogenesis by regulating the localization of Centrin2 at the centrosome.
Résumé
Background & objectives: The objective of the present study was to compare the levels of sperm centrin a centrosomal protein that influences cell migration, in normal fertile donors and in oligoasthenozoospermic males (count 5 million/ml and motility <40%, grade c+d) undergoing intracytoplasmic sperm injection (ICSI) and to correlate with the outcome of ICSI. Methods: The prospective study carried out at Inkus IVF Centre, Mumbai, India, during (January-December 2003). It included 20 normal fertile donor males (group I) and 20 oligoasthnozoospermic (OA) males (group II). Group II was further divided in II a and II b according to the centrin levels. Centrin levels were measured by using enzyme linked immunosorbent assay (ELISA) in both groups. All participants underwent an ICSI procedure and the levels of centrin and outcome of ICSI were correlated. Results: Centrin levels were significantly lower (P<0.001) in group II (0.39) as compared with group I (1.34). With centrin levels <0.45 optical density (OD) (group II a) the pregnancy rate was further reduced, with only 2 pregnancies (out of 14) both of which, ended in abortion. Cases in group II showed levels of centrin much lower than in the fertile group. Further lowered centrin levels were associated with lowered pregnancy rates in OA males, but statistically was not significant. Interpretation & conclusions: The study revealed that lower centrin levels in OA males resulted in lower pregnancy percentage in this group after ICSI. Disturbances in centrosomal protein could be one of the possible causes of ICSI failure.