ISSN:
1423-0127
Keywords:
HIV
;
Duplicated sequence
;
Transcription
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Sequencing of HIV-1GER long terminal repeat (LTR) has demonstrated, for the first time in an HIV-1 primary isolate, a TAR duplication refered to as TAR1 (nucleotides +1 through +68) and TAR2 (nucleotides +69 through +136). This TAR duplication is stable during replication of HIV-1GER isolate in CEM cells. Analysis of LTR-CAT reporter constructs demonstrated that under Tat transactivation the HIV-1GER/LTR (containing TAR1 and TAR2) was expressed at a higher level than a similar construct (HIV-1GERΔTAR) containing a single TAR sequence. Among the two transcription initiation sites found in the HIV-1GER/LTR, only the most 5′ start site was shown to be functionally active. The predicted secondary structure of the 5′-end mRNAs of HIV-1GER suggests it may fold into a double TAR hairpin which resembles that of HIV-2. Finally, HIV-1GER Tat protein shows primary sequence similarity with Tat proteins from other isolates of HIV-1 and is apparently unrelated to HIV-2 Tat proteins. This work provides the first evidence of a TAR sequence duplication in HIV-1 which increases the efficiency of transactivation by Tat.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02253576
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