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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
17
|
| pubmed:dateCreated |
1999-2-5
|
| pubmed:abstractText |
Tat is an essential protein of human immunodeficiency virus type 1 (HIV-1) and activates transcription from the viral long terminal repeat (LTR) promoter. The tat gene is composed of two coding exons of which the first, corresponding to the N-terminal 72 amino acid residues, has been reported to be sufficient for its transcription function. We introduced a stop codon at the end of the first Tat-coding exon in an expression vector that produces a truncated 71-amino acid Tat protein. This Q72stop mutant displays reduced transcriptional activity of approximately 54% in transient LTR-CAT transfection assays. To test the contribution of the second Tat-coding exon to virus replication, the Q72stop mutation was also introduced in the infectious pLAI molecular clone. The effect on virus replication was analyzed in primary cells and in a transformed T cell line. The fitness of the mutant virus was calculated to be approximately 75% compared with the wild-type control. Thus, a small contribution of the C-terminal Tat domain to viral fitness was measured. It has been proposed that the second Tat-coding exon is involved in transcriptional downregulation of the MHC class I gene of the infected host cell. Cell surface expression of the MHC protein was analyzed in T cells infected with the wild-type LAI virus and the replication-competent Q72stop mutant. MHC expression was transiently reduced on infection with either virus, indicating that the second Tat-coding exon is not involved in this downregulation.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Nov
|
| pubmed:issn |
0889-2229
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
20
|
| pubmed:volume |
14
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
1553-9
|
| pubmed:dateRevised |
2007-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:9840288-Animals,
pubmed-meshheading:9840288-COS Cells,
pubmed-meshheading:9840288-Cells, Cultured,
pubmed-meshheading:9840288-Down-Regulation,
pubmed-meshheading:9840288-Exons,
pubmed-meshheading:9840288-Gene Products, tat,
pubmed-meshheading:9840288-HIV Long Terminal Repeat,
pubmed-meshheading:9840288-HIV-1,
pubmed-meshheading:9840288-HeLa Cells,
pubmed-meshheading:9840288-Histocompatibility Antigens Class I,
pubmed-meshheading:9840288-Humans,
pubmed-meshheading:9840288-Transcription, Genetic,
pubmed-meshheading:9840288-Virus Replication,
pubmed-meshheading:9840288-tat Gene Products, Human Immunodeficiency Virus
|
| pubmed:year |
1998
|
| pubmed:articleTitle |
On the role of the second coding exon of the HIV-1 Tat protein in virus replication and MHC class I downregulation.
|
| pubmed:affiliation |
Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, The Netherlands.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|