Preimplantation mouse embryo development. Mus musculus

Studies using low-resolution methods to assess gene expression during preimplantation mouse development indicate that changes in gene expression either precede or occur concomitantly with the major morphological transitions, that is, conversion of the oocyte to totipotent 2-cell blastomeres, compaction, and blastocyst formation. Using microarrays, we characterized global changes in gene expression and used Expression Analysis Systematic Explorer (EASE) to identify biological and molecular processes that accompany and likely underlie these transitions. The analysis confirmed previously described processes or events, but more important, EASE revealed new insights. Response to DNA damage and DNA repair genes are overrepresented in the oocyte compared to 1-cell through blastocyst stages and may reflect the oocyte's response to selective pressures to insure genomic integrity; fertilization results in changes in the transcript profile in the 1-cell embryo that are far greater than previously recognized; and genome activation during 2-cell stage may not be as global and promiscuous as previously proposed, but rather far more selective, with genes involved in transcription and RNA processing being preferentially expressed. These results validate this hypothesis-generating approach by identifying genes involved in critical biological processes that can be the subject of a more traditional hypothesis-driven approach. Keywords: other

采用低分辨率方法评估小鼠植入前发育过程中基因表达的相关研究表明，基因表达变化要么先于主要形态学转变发生，要么与该转变同步出现，这些转变具体包括卵母细胞向全能性2细胞卵裂球的转化、胚胎致密化以及囊胚形成。本研究借助微阵列（microarrays）技术表征了基因表达的全局变化模式，并通过表达分析系统探索器（Expression Analysis Systematic Explorer，EASE）识别出伴随上述转变且可能作为其分子基础的生物学与分子过程。该分析不仅验证了此前已报道的生物学过程或事件，更重要的是，EASE还揭示了全新的研究发现：相较于1细胞至囊胚阶段，卵母细胞中DNA损伤应答与DNA修复基因的富集程度更高，这或反映出卵母细胞为保障基因组完整性而应对选择压力的分子机制；受精过程引发的1细胞胚胎转录组变化幅度远超此前的认知；2细胞阶段的基因组激活或许并不像既往研究所提出的那样具有全局性与非选择性，反而呈现出更强的选择性，其中参与转录与RNA加工过程的基因呈现优先表达特征。本研究通过鉴定可作为传统假说驱动型研究对象的关键生物学过程相关基因，验证了这种假说生成式研究方法的有效性。关键词：其他