title: Alternative RNA splicing of KSHV ORF57 produces two different RNA isoforms.
abstract: In lytically infected B cells Kaposi sarcoma-associated herpesvirus (KSHV) ORF57 gene encodes two RNA isoforms by alternative splicing of its pre-mRNA, which contains a small, constitutive intron in its 5' half and a large, suboptimal intron in its 3's half. The RNA1 isoform encodes full-length ORF57 and is a major isoform derived from splicing of the constitutive small intron, but retaining the suboptimal large intron as the coding region. A small fraction (<5%) of ORF57 RNA undergoes double splicing to produce a smaller non-coding RNA2 due to lack of a translational termination codon. Both RNAs are cleaved and polyadenylated at the same cleavage site CS83636. The insertion of ORF57 RNA1 into a restriction cutting site in certain mammalian expression vectors activates splicing of the subopitmal intron and produces a truncated ORF57 protein.
authors.affiliation: Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, 21702 MD, USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Majerciak
authors.affiliation: Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, 21702 MD, USA. Electronic address: zhengt@exchange.nih.gov.
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Zheng
mesh_terms: D017398:Alternative Splicing; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000502:physiology*; D006801:Humans; D059368:RNA Isoforms / Q000032:analysis*; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics*
chemical_list: C000598480:ORF57 protein, human herpesvirus 8; D059368:RNA Isoforms; D054334:Viral Regulatory and Accessory Proteins
keywords: Alternative splicing; KSHV; ORF57