Elements distinct from human immunodeficiency virus type 1 splice sites are responsible for the Rev dependence of env mRNA.
In the absence of the viral regulatory protein Rev, the human immunodeficiency virus type 1 gag/pol and env mRNAs are inefficiently expressed, since nucleocytoplasmic transport, stability, and polysomal loading are impaired. It has been suggested that splicing is necessary for Rev function and that the low expression of the unspliced and intermediate spliced mRNAs in the absence of Rev is associated with specific splice sites. Previous studies identified distinct RNA elements within the gag/pol region responsible for low expression that are not associated with splice sites. Here we study the determinants for Rev dependence of the authentic env mRNA. We demonstrate that upon removal of all the utilized splice sites, the env mRNA is still Rev dependent and Rev responsive for expression in human cells. We have identified several regions within the env mRNA that inhibit expression of a gag-env hybrid mRNA. Elimination of one of these elements, located within the Rev-responsive element, did not result in virus expression, supporting our model that several independently acting elements are responsible for the downregulatory effect. By analogy to the RNA elements within the gag/pol region, we propose that elements unrelated to utilized splice sites are responsible for the posttranscriptional regulation of env mRNA.
Nasioulas
G
G
Human Retrovirus Pathogenesis Group, National Cancer Institute-Frederick Cancer Research and Development Center, Maryland 21702-1201.
Zolotukhin
A S
AS
Tabernero
C
C
Solomin
L
L
Cunningham
C P
CP
Pavlakis
G N
GN
Felber
B K
BK
D004252:DNA Mutational Analysis; D015536:Down-Regulation; D015686:Gene Products, env / Q000096:biosynthesis*; D015683:Gene Products, gag / Q000235:genetics; D015694:Gene Products, rev / Q000494:pharmacology*; D016655:HIV Core Protein p24 / Q000096:biosynthesis / Q000235:genetics; D015699:HIV Envelope Protein gp120 / Q000235:genetics; D015497:HIV-1 / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D017354:Point Mutation; D012326:RNA Splicing; D012333:RNA, Messenger / Q000096:biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects*; D054321:rev Gene Products, Human Immunodeficiency Virus
D015686:Gene Products, env; D015683:Gene Products, gag; D015694:Gene Products, rev; D016655:HIV Core Protein p24; D015699:HIV Envelope Protein gp120; D012333:RNA, Messenger; D012367:RNA, Viral; D054321:rev Gene Products, Human Immunodeficiency Virus