title: Molecular basis of the internalization of bovine immunodeficiency virus Tat protein.
abstract: Bovine Immunodeficiency Virus (BIV) is a nonacute, pathogenic, and horizontally transmitted lentivirus. It shares the parallel properties in morphology and genetics with human immunodeficiency virus type 1 and other lentiviruses. BIV encodes its own transactivator (BTat), which transactivates its cognate long terminal repeat (LTR). However, the mechanism involved in the transactivation is different from that in HIV and other lentiviruses. We determined the mechanisms of BTat internalization by cells and the effect of BTat on neighboring cells. The green fluorescent protein fusion analysis indicated that the internalization of extracellular BTat was a time and dose-dependent, but endocytosis and energy-independent manner. Arginine residues in the arginine-rich motif (ARM) of BTat were definitively responsible for the internalization. Internalized BTat is predominantly present in the nucleus, resulting in LTR activation and NF-kappaB induction. These results propose that the secretion and internalization of BTat facilitates BIV in influencing neighboring cells and makes the cellular environment propitious to viral replication.
authors.affiliation: Laboratory of Molecular Virology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Deng
authors.forename: Yang
authors.initials: Y
authors.lastname: Su
authors.forename: Junjie
authors.initials: J
authors.lastname: Mu
authors.forename: Rina
authors.initials: R
authors.lastname: Sha
authors.forename: Yunqi
authors.initials: Y
authors.lastname: Geng
authors.forename: Wentao
authors.initials: W
authors.lastname: Qiao
authors.forename: Qimin
authors.initials: Q
authors.lastname: Chen
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001120:Arginine / Q000737:chemistry; D002417:Cattle; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004705:Endocytosis; D015967:Gene Expression Regulation, Viral; D015696:Gene Products, tat / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D016087:Immunodeficiency Virus, Bovine / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020079:Terminal Repeat Sequences; D015533:Transcriptional Activation; D014779:Virus Replication
chemical_list: D015696:Gene Products, tat; D016328:NF-kappa B; D011993:Recombinant Fusion Proteins; D001120:Arginine