Expression and regulation of genes associated with cell death during murine preimplantation embryo development.
The newly fertilized preimplantation embryo depends entirely on maternal mRNAs and proteins deposited and stored in the oocyte prior to its ovulation. If the oocyte is not sufficiently equipped with maternally stored products, or if zygotic gene expression does not commence at the correct time, the embryo will die. One of the major abnormalities observed during early development is cellular fragmentation. We showed previously that cellular fragmentation in human embryos can be attributed to programmed cell death (PCD). Here, we demonstrate that the PCD that occurs during the 1-cell stage of mouse embryogenesis is likely to be regulated by many cell death genes either maternally inherited or transcribed from the embryonic genome. We have demonstrated for the first time the temporal expression patterns of nine cell death regulatory genes, and our preliminary experiments show that the expression of these genes is altered in embryos undergoing fragmentation. The expression of genes involved in cell death (MA-3, p53, Bad, and Bcl-xS) seems to be elevated, whereas the expression of genes involved in cell survival (Bcl-2) is reduced. We propose that PCD may occur by default in embryos that fail to execute essential developmental events during the first cell cycle.
Department of Zoology, University of Toronto, Ontario, Canada.
A
A
Jurisicova
K E
KE
Latham
R F
RF
Casper
R F
RF
Casper
S L
SL
Varmuza
D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D051017:Apoptosis Regulatory Proteins; D001755:Blastocyst / Q000473:pathology / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005809:Genes, Regulator; D006801:Humans; D051379:Mice; D011247:Pregnancy; D011506:Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D016601:RNA-Binding Proteins; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein
D051017:Apoptosis Regulatory Proteins; C494819:BAD protein, human; C494811:BCL2L1 protein, human; C494820:Bad protein, mouse; C494812:Bcl2l1 protein, mouse; D002352:Carrier Proteins; C114487:PDCD4 protein, human; C498443:Pdcd4 protein, mouse; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016601:RNA-Binding Proteins; D016159:Tumor Suppressor Protein p53; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein