Abstract
Genomic imprinting occurs when only one allele of a gene is expressed depending on its parental origin. The imprinted Igf2 gene (Insulin-like growth factor 2) encodes a growth factor that plays an important role in embryonic development and formation of the placenta. The regulation and expression of Igf2 are carried out by different promoters. The promoter expression is extremely complex in wild-type mice during development and is altered in several mutant mice that have deletions at the Igf2/H19 locus. In this experiment, two newly discovered promoters were Pm and Pm2. The expression levels of these two promoters were investigated in different tissues, such as the tongue, kidney, muscle and liver of wild-type mice. We investigated the imprinting levels of the two promoters simultaneously, and they were both highly expressed on the allele derived from the father. All these RNAs were reversely transcribed to cDNA before quantifying the expression levels of the promoters by quantitative PCR (qPCR). Our results show that the transcriptions of the Igf2 Pm and Pm2 promoters are the highest in epidermal tissue. That is why they are named Pm and Pm2 (mesoderme).