PSF acts through the human immunodeficiency virus type 1 mRNA instability elements to regulate virus expression.
Human immunodeficiency virus type 1 (HIV) gag/pol and env mRNAs contain cis-acting regulatory elements (INS) that impair stability, nucleocytoplasmic transport, and translation by unknown mechanisms. This downregulation can be counteracted by the viral Rev protein, resulting in efficient export and expression of these mRNAs. Here, we show that the INS region in HIV-1 gag mRNA is a high-affinity ligand of p54nrb/PSF, a heterodimeric transcription/splicing factor. Both subunits bound INS RNA in vitro with similar affinity and specificity. Using an INS-containing subgenomic gag mRNA, we show that it specifically associated with p54nrb in vivo and that PSF inhibited its expression, acting via INS. Studying the authentic HIV-1 mRNAs produced from an infectious molecular clone, we found that PSF affected specifically the INS-containing, Rev-dependent transcripts encoding Gag-Pol and Env. Both subunits contained nuclear export and nuclear retention signals, whereas p54nrb was continuously exported from the nucleus and associated with INS-containing mRNA in the cytoplasm, suggesting its additional role at late steps of mRNA metabolism. Thus, p54nrb and PSF have properties of key factors mediating INS function and likely define a novel mRNA regulatory pathway that is hijacked by HIV-1.
Zolotukhin
Andrei S
AS
Human Retrovirus Pathogenesis Section, Basic Research Laboratory, National Cancer Institute-Frederick Cancer Research and Development Center, Frederick, MD 21702-1201, USA.
Michalowski
Daniel
D
Bear
Jenifer
J
Smulevitch
Sergey V
SV
Traish
Abdulmaged M
AM
Peng
Rui
R
Patton
James
J
Shatsky
Ivan N
IN
Felber
Barbara K
BK
D002478:Cells, Cultured / Q000821:virology; D004268:DNA-Binding Proteins; D015685:Fusion Proteins, gag-pol / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D015686:Gene Products, env / Q000235:genetics / Q000378:metabolism; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism; D015694:Gene Products, rev / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D034521:Nuclear Matrix-Associated Proteins / Q000235:genetics / Q000378:metabolism; D050810:Octamer Transcription Factors; D000072670:PTB-Associated Splicing Factor; D011533:Proviruses / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D038621:Regulatory Sequences, Ribonucleic Acid; D054321:rev Gene Products, Human Immunodeficiency Virus
D004268:DNA-Binding Proteins; D015685:Fusion Proteins, gag-pol; D015686:Gene Products, env; D015683:Gene Products, gag; D015694:Gene Products, rev; C083214:NONO protein, human; D034521:Nuclear Matrix-Associated Proteins; D050810:Octamer Transcription Factors; D000072670:PTB-Associated Splicing Factor; D012333:RNA, Messenger; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D054321:rev Gene Products, Human Immunodeficiency Virus