Genetic regulation of preimplantation mouse embryo survival

Abstract

The preimplantation period of mammalian development is characterized by cleavage of a one-cell embryo to a blastocyst stage embryo. During preimplantation development, 15%-50% of the embryos die as a result of factors that are largely unknown. Two parameters of preimplantation development, a fast rate of development and a low degree of fragmentation, are indicative of good embryo quality. There is mounting evidence that genes control both rate of development and degree of fragmentation. We have discovered a gene, Ped (preimplantation embryo development), which controls the rate of preimplantation embryonic cleavage. The Ped gene is encoded by two similar genes, Q7 and Q9, in the Q region of the mouse major histocompatibility complex (MHC). The Ped gene product is an MHC class Ib protein, the Qa-2 antigen. The mechanisms by which the Ped gene controls rate of embryonic cleavage division are being explored. In order to understand genetic mechanisms underlying the second criterion of embryo quality, degree of fragmentation, we have begun to assess expression of the genes that could potentially regulate apoptosis in preimplantation embryos. We have shown that staurosporine can induce apoptosis in mouse blastocysts. By using RT-PCR, we have shown that genes encoding protein in the two major gene families that regulate apoptosis, the Bcl-2 and caspase gene families, are present in preimplantation embryos. We hypothesize that there is a homeostatic mechanism by which genes that regulate cell survival and those that regulate cell death determine the overall viability of preimplantation embryos.

Depletion of BIRC6 leads to retarded bovine early embryonic development and blastocyst formation in vitro

“…al 2007). However, embryo survival and viability is mainly limited by the degree of fragmentation or the extent of apoptosis (Warner et al 1998;Alikani et al 1999). This, in turn, depends on transcripts that regulate cell survival (anti-apoptotic) and cell death (proapoptotic) (Warner et al 1998).…”

“…However, embryo survival and viability is mainly limited by the degree of fragmentation or the extent of apoptosis (Warner et al 1998;Alikani et al 1999). This, in turn, depends on transcripts that regulate cell survival (anti-apoptotic) and cell death (proapoptotic) (Warner et al 1998). Hence, the ratio of pro-apoptotic to anti-apoptotic transcripts determines whether the cell will live or die (Oltval et al 1993;Reed 1997; Bartke et al 2004).…”

小鼠早期胚胎内细胞凋亡的一个量化模型

“…Laurie 等人 [10] 的研究指出, 非整倍性卵裂球中染色体 的分布趋于细胞核外围区, 且这种外围化预示了胚 胎的死亡. 前人的工作主要集中于凋亡现象的信号通路和 基因调控 [13,14] , 而在介观或宏观层次上对凋亡过程 的量化研究则较少.…”

Interação cumulus e oócito no processo de morte celular programada durante a produção de embriões bovinos in vitro

“…Esta contém diferentes moléculas (transcritos e proteínas) pró e anti-apoptóticas (MEIRELLES et al, 2004). A presença de muitas destas moléculas, seja como transcritos de genes ou como proteínas relacionadas à sobrevivência celular, vem sendo observada em oócitos e embriões (JURISICOVA et al, 1998;WARNER et al, 1998;PEREZ et al, 1999;YANG;RAJAMAHENDRAN, 2002). Estudos mostraram que a injeção intracitoplasmática de isolado de mitocôndria pode ser suficiente para salvar um oócito da fragmentação celular (PEREZ et al, 1999.…”