| Abstract: | We have determined the entire nucleotide sequence of an intra-cisternal A particle (IAP) genome, associated with the Ren-2 gene of DBA/2 mice. This genome (MIARN) displays features common to other IAP retroviral-like genomes. Long terminal repeats (LTRs) are approximately 430 base pairs (bp) in length and show typical retroviral U3-R-U5 organisation, though the R-region, at 120 bp, is much larger than the average IAP. This difference probably arose by the amplification of a pyrimidine-rich sequence, by a slippage-mispairing mechanism. Flanking the 5' LTR is a sequence complementary to a phenylalanine tRNA, strongly conserved in all rodent IAP genomes and probably required to prime the initiation of (-) strand synthesis. Flanking the 3' LTR, is a purine-rich sequence probably required for (+) strand synthesis. The tRNA binding site (TBS) is flanked by six tandem copies of a sequence homologous to the TBS. The relationship of the MIARN element to other IAP genomes and the significance of its association with the highly expressed Ren-2 is discussed. |
