Acetylated Tat regulates human immunodeficiency virus type 1 splicing through its interaction with the splicing regulator p32.
The human immunodeficiency virus type 1 (HIV-1) potent transactivator Tat protein mediates pleiotropic effects on various cell functions. Posttranslational modification of Tat affects its activity during viral transcription. Tat binds to TAR and subsequently becomes acetylated on lysine residues by histone acetyltransferases. Novel protein-protein interaction domains on acetylated Tat are then established, which are necessary for both sustained transcriptional activation of the HIV-1 promoter and viral transcription elongation. In this study, we investigated the identity of proteins that preferentially bound acetylated Tat. Using a proteomic approach, we identified a number of proteins that preferentially bound AcTat, among which p32, a cofactor of splicing factor ASF/SF-2, was identified. We found that p32 was recruited to the HIV-1 genome, suggesting a mechanism by which acetylation of Tat may inhibit HIV-1 splicing needed for the production of full-length transcripts. Using Tat from different clades, harboring a different number of acetylation sites, as well as Tat mutated at lysine residues, we demonstrated that Tat acetylation affected splicing in vivo. Finally, using confocal microscopy, we found that p32 and Tat colocalize in vivo in HIV-1-infected cells.
Berro
Reem
R
Genetics Program, The George Washington University, Washington, DC 20037, USA.
Kehn
Kylene
K
de la Fuente
Cynthia
C
Pumfery
Anne
A
Adair
Richard
R
Wade
John
J
Colberg-Poley
Anamaris M
AM
Hiscott
John
J
Kashanchi
Fatah
F
D000107:Acetylation; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D019084:Fluorescent Antibody Technique, Indirect; D015967:Gene Expression Regulation, Viral; D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D018613:Microscopy, Confocal; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008957:Models, Genetic; D040901:Proteomics; D012326:RNA Splicing; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D054322:tat Gene Products, Human Immunodeficiency Virus
C087299:C1QBP protein, human; D002352:Carrier Proteins; D015696:Gene Products, tat; D024101:Mitochondrial Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus; D008156:Luciferases; D015500:Chloramphenicol O-Acetyltransferase