Gene expression profiling of human oocytes following in vivo or in vitro maturation.
BACKGROUND
Immature human oocytes matured in vitro, particularly those from gonadotrophin stimulated ovaries, are developmentally incompetent when compared with oocytes matured in vivo. This developmental incompetence has been explained as poor oocyte cytoplasmic maturation without any determination of the likely molecular basis of this observation.


METHODS
Replicate whole human genome arrays were generated for immature and mature oocytes (matured in vivo and in vitro, prior to exposure to sperm) recovered from women undertaking gonadotrophin treatment for assisted reproduction.


RESULTS
More than 2000 genes were identified as expressed at more than 2-fold higher levels in oocytes matured in vitro than those matured in vivo (P < 0.05, range 4.98 x 10(-2) -2.22 x 10(-4)) and 162 of these are expressed at 10-fold or greater levels (P < 0.05, range 4.98 x 10(-2)-1.38 x 10(-3)). Many of these genes are involved in transcription, the cell cycle and its regulation, transport and cellular protein metabolism.


CONCLUSIONS
Global gene expression profiling using microarrays and bioinformatics analysis has provided a molecular basis for differences in the developmental competence of oocytes matured in vitro compared with in vivo. The over-abundance of transcripts identified in immature germinal vesicle stage oocytes recovered from gonadotrophin stimulated cycles and matured in vitro is probably due to dysregulation in either gene transcription or post-transcriptional modification of genes. Either mechanism would result in an incorrect temporal utilization of genes which may culminate in developmental incompetence of any embryos derived from these oocytes.
Jones
Gayle M
GM
Monash Immunology and Stem Cell Laboratories, Monash University, Level 3, STRIP Building 75 Wellington Road, Clayton, VIC 3800, Australia. gayle.jones@med.monash.edu.au
Cram
David S
DS
Song
Bi
B
Magli
M Cristina
MC
Gianaroli
Luca
L
Lacham-Kaplan
Orly
O
Findlay
Jock K
JK
Jenkin
Graham
G
Trounson
Alan O
AO
D005260:Female; D020869:Gene Expression Profiling; D015894:Genome, Human / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D020411:Oligonucleotide Array Sequence Analysis; D009865:Oocytes / Q000502:physiology*; D013480:Superovulation