C. Magin et al., cORF and RcRE, the Rev/Rex and RRE/RxRE homologues of the the human endogenous retrovirus family HTDV/HERV-K, J VIROLOGY, 73(11), 1999, pp. 9496-9507
cORF, a protein encoded by the human endogenous retrovirus family HTDV/HERV
-K, contains amino acid motifs which resemble the nuclear import and export
signals of the viral regulatory proteins Rev (human immunodeficiency virus
) and Rex (human T-cell leukemia virus [HTLV]). In this study, me demonstra
ted that cORF indeed has a Rev-like function and mapped the cORF-responsive
RNA element to a sequence in the 3' long terminal repeat, a localization s
imilar to RxRE, the responsive element in HTLV type 1. Accordingly, me have
given the element the designation RcRE. cORF and RcRE stabilize unspliced
and incompletely spliced viral transcripts and enhance their nuclear export
via the CRM1 export pathway. So far, HTDV/HERV-K is the only endogenous re
trovirus family with a complex regulation at the posttranscriptional level.
It may be regarded as an intermediate in the evolution from simple to comp
lex retroviruses.