Expression of the insulin-like growth factor-1 gene and its receptor in preimplantation mouse embryos; is it a marker of embryo viability?
Recent studies have demonstrated the importance of insulin-like growth factors (IGF) in mouse preimplantation development. We examined IGF-1 and IGF-1 receptor (IGF-1R) gene expression in a single blastomere of an early mouse embryo and compared it with subsequent embryo development in culture. Fertilized eggs and 2-cell embryos were obtained by tubal flushing in superovulated and mated female mice. Single cells were removed from embryos at cleavage stage between 3 and 8 cells using the standard embryo biopsy techniques. Individual blastomeres from each embryo were then assayed for the presence of IGF-1 and IGF-1R mRNA using reverse transcription-polymerase chain reaction. The biopsied embryos were washed in medium and placed in co-culture with murine endometrial cells. Embryonic development in culture was assessed and blastocyst grading was performed. IGF-1 gene expression was then examined for an association with in-vitro development. Eighty-seven embryos were biopsied. IGF-1R gene expression was detected in the majority of embryos tested and IGF-1 gene expression was detected in 34 of 81 (42%) embryos. A significant association between IGF-1 expression and blastocyst formation in vitro was found (P < 0.01). There was no association between IGF-1R expression and subsequent embryo development. We conclude that IGF-1 gene expression could potentially be used as a marker of embryo quality.
Kowalik
A
A
The Center for Reproductive Medicine and Infertility, Department of Obstetrics and Gynecology, The New York Hospital-Cornell Medical Center, New York, NY 10021, USA.
Liu
H C
HC
He
Z Y
ZY
Mele
C
C
Barmat
L
L
Rosenwaks
Z
Z
D000199:Actins / Q000235:genetics; D000818:Animals; D001757:Blastomeres; D046508:Culture Techniques; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D005328:Fetal Viability / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D005819:Genetic Markers; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D051379:Mice; D008815:Mice, Inbred Strains; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D017526:Receptor, IGF Type 1 / Q000235:genetics*
D000199:Actins; D005819:Genetic Markers; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1