Retroviral-like features in the monomer of the major satellite DNA from the South American rodents of the genus Ctenomys

Abstract

It is well known that uninfected mammalian cells contain DNA sequences which are closely related to retroviral genomic segments. However, these sequences seldom (if ever) have been found associated to highly repetitive (satellite) DNA. RPCS is a 348 bp monomer of a major satellite DNA from the South American rodents of the genus Ctenomys. It was found that RPCS contains several elements which are typical of the U3 region of retroviral LTRs. These elements are: a) a polypurine tract; b) two enhancer core sequences; c) two NF1 binding sites; d) two C/EBP binding sites; e) two CCAAT-motifs; f) a TATA box, and g) two putative polyadenylation motifs. Furthermore, the relative positions of these elements are as in the U3 retroviral regions.

Molecular characterization of the complex sex-chromosome heterochromatin in the rodent Microtus chrotorrhinus

“…Similarity between MSAT-160 and the RPCS satellite from the South American rodent Ctenomys (Rossi et al, 1993) was found, and these two DNA sequences were aligned. The IR ele ments of MSAT-160 have similarity to two pairs of IRs located in the terminal and central regions of RPCS, viz., the reported 348-bp repeat unit appears to be a dimer consisting of two unre lated subunits of approximately equal length (Fig.…”

“…This 14-bp motif immediately precedes the start of MSAT-21 and reveals that the terminal (or junction) monomer of MSAT-160 is full length, as is the first (or junction) mono mer of MSAT-21; i.e., no deletions in either satellite or inser tions of foreign DNA exist at the junction. The only unusual Rossi et al (1993).…”

“…Pre viously, three protein binding domains in addition to certain retroviral hallmarks (e.g., a polypurine tract, a TATA box, and two putative polvadenylation motifs) have been identified in the RPCS repeat (Rossi et al" 1993;Pesce et al. 1994).…”

“…Further, since sequence similarities between RPCS and the 234-bp U3 region of the Rous sarcoma virus (RSV) long termi Cytogenet Cell Genet 75: 49-56 (1996)nal repeat (LTR) had been suggested (Rossi et al, 1993), MSAT-160 was compared to this viral sequence as well. The RSV LTR is Hanked by IRs.…”

G-banding patterns of the genusCtenomysfrom Uruguay (Rodentia Ctenomydae): high karyotype variation but chromosome arm conservation

“…The major satellite DNA of tuco-tucos, named RPCS (repetitive PuvII Ctenomys sequence), is organized in long arrays of 348 bp monomer units (Novello et al 1988;Rossi et al 1990). In situ hybridization showed that RPCS mainly localizes in different chromosomal regions positive for C-banding: whole arms and pericentromeric blocks, as well as telomeric and interstitial bands (Rossi et al 1993;Novello et al 1996) in mitotic and meiotic cells (Novello and Villar 2006).…”