Kojima Yoji, Tam Oliver H, Tam Patrick P L
Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8501, Japan.
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Semin Cell Dev Biol. 2014 Oct;34:65-75. doi: 10.1016/j.semcdb.2014.06.010. Epub 2014 Jun 17.
The timing of developmental events during early mouse development has been investigated in embryos that have been subject to experimental manipulation of cell number and tissue mass. These phenomenological studies revealed that the timing of preimplantation events, such as compaction, formation of blastocyst cavity and lineage allocation is correlated with the rounds of cleavage division or DNA replication of the blastomeres. Timing of postimplantation processes, such as formation of proamniotic cavity and onset of gastrulation is sensitive to cell number and probably the tissue mass, which may be measured by a mechanosensory signaling mechanism. Developmental changes in these two physical attributes are correlated with the cell proliferative activity and the growth trajectory of the whole embryo prior to the transit to organogenesis. During organogenesis, timing of morphogenesis appears to be regulated by individual devices that could be uncoupled during compensatory growth. Insights of the timing mechanism may be gleaned from the analysis of genomic activity associated with the transition through developmental milestones.
在经过细胞数量和组织质量实验操作的小鼠胚胎中，研究了小鼠早期发育过程中发育事件的时间安排。这些现象学研究表明，着床前事件的时间安排，如致密化、囊胚腔形成和谱系分配，与卵裂球的分裂轮次或DNA复制相关。着床后过程的时间安排，如羊膜腔形成和原肠胚形成的开始，对细胞数量敏感，可能也对组织质量敏感，这可能通过机械感觉信号机制来衡量。在过渡到器官发生之前，这两个物理属性的发育变化与细胞增殖活性和整个胚胎的生长轨迹相关。在器官发生过程中，形态发生的时间似乎由个体机制调节，这些机制在代偿性生长过程中可能会解耦。通过分析与发育里程碑转变相关的基因组活性，可能会获得对时间机制的见解。
