The Herpesvirus saimiri small nuclear RNAs recruit AU-rich element-binding proteins but do not alter host AU-rich element-containing mRNA levels in virally transformed T cells.
Herpesvirus saimiri (HVS) encodes seven Sm-class small nuclear RNAs, called HSURs (for Herpesvirus saimiri U RNAs), that are abundantly expressed in HVS-transformed, latently infected marmoset T cells but are of unknown function. HSURs 1, 2, and 5 have highly conserved 5'-end sequences containing the AUUUA pentamer characteristic of AU-rich elements (AREs) that regulate the stability of many host mRNAs, including those encoding most proto-oncogenes and cytokines. To test whether the ARE-containing HSURs act to sequester host proteins that regulate the decay of these mRNAs, we demonstrate their in vivo interaction with the ARE-binding proteins hnRNP D and HuR in HVS-transformed T cells using a new cross-linking assay. Comprehensive Northern and microarray analyses revealed, however, that the levels of endogenous ARE-containing mRNAs are not altered in T cells latently infected with HVS mutants lacking HSURs 1 and 2. HSUR 1 binds the destabilizing ARE-binding protein tristetraprolin induced following activation of HVS-transformed T cells, but even in such stimulated cells, the levels of host ARE-containing mRNAs are not altered by deletion of HSURs 1 and 2. Instead, HSUR 1 itself is degraded by an ARE-dependent pathway in HVS-transformed T cells, suggesting that HVS may take advantage of the host ARE-mediated mRNA decay pathway to regulate HSUR expression. This is the first example of posttranscriptional regulation of the expression of an Sm small nuclear RNA.
Cook
Heidi L
HL
Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06536, USA.
Mischo
Hannah E
HE
Steitz
Joan A
JA
D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D001482:Base Composition; D001483:Base Sequence; D002144:Callithrix; D002460:Cell Line; D002472:Cell Transformation, Viral; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D006567:Herpesvirus 2, Saimiriine / Q000235:genetics* / Q000378:metabolism*; D034502:Heterogeneous-Nuclear Ribonucleoprotein D / Q000378:metabolism; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism*; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism* / Q000821:virology*
D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D034502:Heterogeneous-Nuclear Ribonucleoprotein D; D012333:RNA, Messenger; D012342:RNA, Small Nuclear; D012367:RNA, Viral; D016601:RNA-Binding Proteins