Transcriptional Regulation of Long-terminal Repeat of Intracisternal A-particle that Contributes Gene Rearrangement in Radiation-induced Myeloid Leukemia in C3H Mice.

Abstract

Mouse genome possesses 2000 copies of the retrotransposon, intracisternal A-particle (IAP) DNA element, that closely resembles to provirus of retrovirus. We have previously classified long-terminal repeat (LTR) of IAP elements in genome by its nucleotide sequence variation to type-A to H. The integration of IAP cDNA with H-type LTR into genomic DNA to generate illegitimate structure is frequently observed in radiation-induced acute myeloid leukemia (AML) cells in C3H/He mice. Since production of the IAP RNA is the first step of retrotransposition mechanisms and is regulated by the 5'-LTR, we compared transcriptional activity of the LTRs of type-A, D and H by the reporter assay. Transcriptions driven by D-type LTR and H-type LTR were enhanced in Balb/c-based and C3H/He-based hematopoietic cell lines, respectively. Nucleotide sequences essential for mouse strain and tissue specific regulation site in U3-region of LTR were determined. [J Radiat Res 44:395-396 (2003)]