A cis-Acting Element Downstream of the Mouse Mammary Tumor Virus Major Splice Donor Critical for RNA Elongation and Stability

Abstract

MMTV contains a novel cis-acting element downstream of the major splice donor critical for facilitating MMTV gRNA elongation and stability. Presence of a mirror repeat within the element may represent important viral/host factor binding site(s) within MMTV gRNA.

A Novel, Fully Spliced, Accessory Gene in Equine Lentivirus with Distinct Rev-Responsive Element

“…Rem is an accessory protein encoded by mouse mammary tumor virus (MMTV) and is a homolog of the Rev protein in lentivirus. MMTV, a member of the genus Betaretrovirus, harbors two Rem-responsive elements (RmREs): a 5’RmRE located at the 5’UTR of gRNA that is required for nuclear export of unspliced RNA, and a 3′ RmRE located at env-U3 junction region that is needed for expression of both unspliced and spliced transcripts ( 54 ). Therefore, EIAV is different from HIV-1 and MMTV in that its two RREs are in the coding region sequence.…”

A novel fully-spliced accessory gene in equine lentivirus with distinct Rev-responsive element

“…Rem is an accessory protein encoded by mouse mammary tumor virus (MMTV) and is a homolog of the Rev protein in lentivirus. MMTV, a member of the genus Betaretrovirus, harbors two Rem-responsive elements (RmREs): a 5’RmRE located at the 5’UTR of gRNA that is required for nuclear export of unspliced RNA, and a 3’ RmRE located at env-U3 junction region that is needed for expression of both unspliced and spliced transcripts [46]. Therefore, EIAV is different from HIV-1 and MMTV in that its two RREs are located in the coding region sequence.…”

Role of Purine-Rich Regions in Mason-Pfizer Monkey Virus (MPMV) Genomic RNA Packaging and Propagation

“…HEK 293T cells transfected with different mutant and/or wild-type vectors were harvested from the six-well plates, and a portion of cells were fractionated into nuclear and cytoplasmic fractions, as described previously ( Akhlaq et al, 2018 ; Supplementary Figure 1 ). The cytoplasmic and packaged viral RNAs were isolated from Trizol following manufacturer’s instructions (Invitrogen, United States).…”

“…HEK 293T cells transfected with different mutant and/or wild-type vectors were harvested from the six-well plates, and a portion of cells were fractionated into nuclear and cytoplasmic fractions, as described previously (Akhlaq et al, 2018; FIGURE 2 | Description of the mutations introduced in ssPurines and bpPurines, RT-qPCR and virus titer analysis of ssPurines and bpPurines mutants to establish their role in MPMV RNA packaging and propagation. (A) Table describing the nature of the mutations introduced and cloned both in the context of the sub-genomic transfer and in vitro transcription vectors.…”