PDF(Pubmed)
Abstract：
Centrioles are the core constituent of centrosomes, microtubule-organizing centers involved in directing mitotic spindle assembly and chromosome segregation in animal cells. In sexually reproducing species, centrioles degenerate during oogenesis and female meiosis is usually acentrosomal. Centrioles are retained during male meiosis and, in most species, are reintroduced with the sperm during fertilization, restoring centriole numbers in embryos. In contrast, the presence, origin, and function of centrioles in parthenogenetic species is unknown. We found that centrioles are maternally inherited in two species of asexual parthenogenetic nematodes and identified two different strategies for maternal inheritance evolved in the two species. In Rhabditophanes diutinus, centrioles organize the poles of the meiotic spindle and are inherited by both the polar body and embryo. In Disploscapter pachys, the two pairs of centrioles remain close together and are inherited by the embryo only. Our results suggest that maternally-inherited centrioles organize the embryonic spindle poles and act as a symmetry-breaking cue to induce embryo polarization. Thus, in these parthenogenetic nematodes, centrioles are maternally-inherited and functionally replace their sperm-inherited counterparts in sexually reproducing species.
摘要：
中心粒是中心体的核心组成部分，涉及指导动物细胞有丝分裂纺锤体组装和染色体分离的微管组织中心。在有性繁殖的物种中，在卵子发生和雌性减数分裂过程中，中心粒退化通常是中心体。在男性减数分裂期间保留中心粒，在大多数物种中，在受精过程中重新引入精子，恢复胚胎中的中心粒数。相比之下,存在,origin,和中心粒在孤雌生殖物种中的功能是未知的。我们发现中心粒在两种无性孤雌生殖线虫中母系遗传，并确定了两种不同的母系遗传策略。在杜蒂诺斯，中心粒组织减数分裂纺锤体的两极，并由极体和胚胎遗传。在Disploscapterpachys中，两对中心粒保持在一起，只由胚胎遗传。我们的结果表明，母本遗传的中心粒组织了胚胎纺锤体的两极，并充当对称破坏线索以诱导胚胎极化。因此，在这些孤雌生殖线虫中，中心粒是母系遗传的，在有性繁殖物种中在功能上取代了精子遗传的对应物。
