Functional Expression Study ofIgf2Antisense Transcript in Mouse

Abstract

Insulin-like growth factor antisense gene (Igf2as) expression was investigated in different mouse tissues during development, in differentiating C2C12 cells and in aΔDMR1-U2 knockout mouse model. The expression levels ofIgf2aswere high in fetal and newborn liver and muscle tissues compared to adults. TheIgf2asgene was also expressed in placenta and in brain. The expression data suggests that theIgf2asgene plays a role in early development of the mouse and in placenta. There was no consistent evidence for an interaction betweenIgf2andIgf2astranscripts. Furthermore, in knockout placentas lackingIgf2astranscription,Igf2expression was comparable to that in wild type. These results indicate thatIgf2asdoes not regulateIgf2sense transcripts. In previous studies, it was suggested that theΔDMR1-U2 knockout mouse showing intrauterine growth restriction was caused by the absence of placenta-specificIgf2P0 transcription. We conclude that theΔDMR1-U2 deletion phenotype should be reconsidered in the light of a functionalIgf2asgene.