title: Timing of developmental events in the early mouse embryo.
abstract: 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.
authors: Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8501, Japan. Electronic address: ykojima@icems.kyoto-u.ac.jp.
authors: Yoji
authors: Y
authors: Kojima
authors: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA. Electronic address: tam@cshl.edu.
authors: Oliver H
authors: OH
authors: Tam
authors: Embryology Unit, Children's Medical Research Institute and Sydney Medical School, University of Sydney, Westmead, NSW 2145, Australia. Electronic address: ptam@cmri.org.au.
authors: Patrick P L
authors: PP
authors: Tam
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000502:physiology*; D001757:Blastomeres / Q000502:physiology; D054262:Gastrulation; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D051379:Mice; D009024:Morphogenesis; D059467:Transcriptome
keywords: Gastrulation; Morphogenesis; Mouse embryo; Timing mechanism; Transcriptome