Space asymmetry directs preferential sperm entry in the absence of polarity in the mouse oocyte.

ABSTRACT: Knowledge about the mechanism that establishes embryonic polarity is fundamental in understanding mammalian development. In re-addressing several controversial claims, we recently proposed a model in which mouse embryonic polarity is not specified until the blastocyst stage. Before fertilization, the fully differentiated oocyte has been characterized as "polarized," and we indeed observed that the sperm preferentially enters the polar body half. Here we show that preferential sperm entry is not due to an intrinsic polarity of the oocyte, since fertilization takes place uniformly when the zona pellucida is removed. We suggest that the term "asymmetry" denotes morphological differences, whereas "polarity" in addition implies developmental consequences. Thus, the mouse oocyte can be considere

SUBMITTER: Motosugi N 

PROVIDER: S-EPMC1440932 | biostudies-literature | 2006 May

REPOSITORIES: biostudies-literature