Expression profiling of DNA repair genes in human oocytes and blastocysts using microarrays.
BACKGROUND
The early preimplantation embryo relies on mRNA and protein from the oocyte to detect DNA damage and activate DNA repair, cell cycle arrest or apoptosis. Expression of some repair genes has been detected in mammalian oocytes and embryos; however, little is known about DNA repair gene expression in human blastocysts. In this study, DNA repair gene expression was investigated in human oocytes and blastocysts to identify the pathways involved at these stages and detect potential differences in repair mechanisms pre- and post-embryonic genome activation.


METHODS
Triplicate sets of pooled metaphase II oocytes or blastocysts were processed for analysis using the Human Genome Survey Microarrays V2.0 (Applied Biosystems).


RESULTS
Of 154 DNA repair genes investigated, 109 were detected in blastocysts and 107 in oocytes. Among differentially expressed DNA repair genes, 40/55 (73%) had lower expression levels in blastocysts compared with oocytes (P < 0.05, fold change >3).


CONCLUSIONS
Despite experimental limitations due to culture or freezing and thawing of samples, large numbers of repair genes were detected indicating that all DNA repair pathways are potentially functional in human oocytes and blastocysts. The higher mRNA level for most repair genes in oocytes compared with blastocysts ensures sufficient availability of template until embryonic genome activation.
Jaroudi
Souraya
S
UCL Centre for PGD, Institute for Women's Health, University College London, 86-96 Chenies Mews, London WC1E 6HX, UK.
Kakourou
Georgia
G
Cawood
Suzanne
S
Doshi
Alpesh
A
Ranieri
Domenico M
DM
Serhal
Paul
P
Harper
Joyce C
JC
SenGupta
Sioban B
SB
D001755:Blastocyst / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics* / Q000502:physiology; D020869:Gene Expression Profiling; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D009865:Oocytes / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
D012333:RNA, Messenger