Construction of transgenic mouse to measure reverse transcription of retrotransposon IAP based on C3H/He.

Abstract

C3H/He inbred mice frequently generate myeloid leukemia after sublethal doses of ionizing radiation. We previously found that the unique genomic insertion of cDNA of retrotransposon, intracisternal A-particle (IAP), is frequently detected in radiation-induced myeloid leukemia cells in the C3H/He mice. To investigate synthesis of IAP cDNA in C3H/He mouse, our original methodology to measure reverse transcription in cell lines was expanded to the generation of transgenic mouse in this study.
A transgene designed to express Idelta1-IAP RNA with 4 blocks of unique oligonucleotide as molecular markers was constructed. By the direct injection of the 12.5 kb DNA into embryos of C3H/He inbred mouse, we succeeded in generation of transgenic mice and bred the F1 and F2 offsprings. Quantitative analysis of nucleic acids from peripheral blood of each individual showed that copy numbers and RNA levels of the transgenic IAP element were stabilized in F1 generation and afterward. Using the molecular marker-specific PCR, we detected cDNA that was specifically synthesized from transgene IAP RNA, suggesting that retroviral reverse transcription was detectable in the transgenic mouse.