The Effect of a Single Nucleotide Substitution in the Splicing Silencer in the tat/rev Intron on HIV Type 1 Envelope Expression.
A complex mRNA splicing pattern, which remains to be fully characterized, influences HIV-1 gene expression. In this study, poor envelope expression of a primary HIV-1 isolate was observed and linked to increased splicing of the two coding exons of tat/rev. The substitution of a nucleotide G, located 28 nucleotides upstream of the splice acceptor site SA7 in the recently identified intron splicing silencer sequence, was found to be responsible for the poor envelope expression. A single nucleotide substitution of G with A at this position results in a poor envelope expression phenotype. Moreover, substitution of the nucleotide G with any other nucleotide in an infectious HIV-1 proviral clone, HXB2RU3, results in poor envelope expression. The substitution of this nucleotide reduces the hnRNP A1 binding affinity but increases the splicing of env mRNA. The nucleotide G at this position is highly conserved among HIV-1 isolates and appears to play a critical role in HIV-1 splicing.
Paca-Uccaralertkun
Saowakon
S
Department of Microbiology, Faculty of Science, Mahidol University, Payatai, Bangkok 10400, Thailand.
Damgaard
Christian Kroun
CK
Auewarakul
Prasert
P
Thitithanyanont
Arunee
A
Suphaphiphat
Pirada
P
Essex
Max
M
Kjems
Jørgen
J
Lee
Tun-Hou
TH
D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D015870:Gene Expression; D015694:Gene Products, rev / Q000235:genetics*; D020868:Gene Silencing; D015756:Genes, tat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D007438:Introns / Q000235:genetics*; D017354:Point Mutation; D011485:Protein Binding; D012326:RNA Splicing / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D054321:rev Gene Products, Human Immunodeficiency Virus
D015694:Gene Products, rev; D012333:RNA, Messenger; D012367:RNA, Viral; D054321:rev Gene Products, Human Immunodeficiency Virus