PMID- 2778873
OWN - NLM
STAT- MEDLINE
DCOM- 19891017
LR  - 20200724
IS  - 0022-538X (Print)
IS  - 1098-5514 (Electronic)
IS  - 0022-538X (Linking)
VI  - 63
IP  - 10
DP  - 1989 Oct
TI  - Characterization of enhancer elements and their mutations in the long terminal 
      repeat of feline endogenous RD-114 proviruses.
PG  - 4234-41
AB  - To locate the enhancer regions of the feline endogenous RD-114 long terminal 
      repeat (LTR), we examined expression of the chloramphenicol acetyltransferase 
      gene driven by various segments of the U3 region from two different proviral loci 
      (CRL3 and CR1). Transient expression assays demonstrated that the primary signal 
      sequence for transcription enhancement was located within the 63-base-pair (bp) 
      element of the CRL3 DNA occurring between positions -184 and -121 from the CAP 
      site (+1), whereas the similar region of CR1 was almost inactive. This element 
      from both CRL3 and CR1 contained a single 30-bp sequence (direct repeat [DR]-B2) 
      found in duplicate tandem copies in the LTR of the infectious RD-114 provirus. 
      Two 9-bp inverted repeats marked the DR-B unit of the active element, and a 
      prominent base deletion in one of these repeats in CR1 DNA appeared to be related 
      to loss of enhancer activity. Another segment of CRL3 (-296 to -184), also 
      displaying enhancer function, contained tandem repeated sequences (DR-A1 and 
      DR-A2). The Dr-A2 unit, which lacked the 5' 20-bp sequence of the 47-pb DR-A1, 
      could not function as an enhancer by itself, but it contributed to enhancer 
      effects in cooperation with either the DR-A1 or DR-B2 region. The CR1 LTR 
      contained a single DR-A1 sequence with extensive mutations, and the region (-313 
      to -181) containing this DR-A1 unit was nonfunctional, similar to the DR-B2 
      region of CR1. Site-directed mutagenesis analysis of another enhancer element, an 
      octamer motif occurring between CAAT and TATA boxes of all RD-114 LTRs sequenced, 
      revealed that this element was necessary for full enhancer function of the U3 
      region but with a variable effect, depending on the cell types in which 
      chloramphenicol acetyltransferase expression was determined.
FAU - Ghosh, A K
AU  - Ghosh AK
AD  - Department of Pathology, University of Southern California, School of Medicine, 
      Los Angeles 90033.
FAU - Roy-Burman, P
AU  - Roy-Burman P
LA  - eng
GR  - CA 40590/CA/NCI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Virol
JT  - Journal of virology
JID - 0113724
RN  - 0 (DNA, Viral)
SB  - IM
MH  - Animals
MH  - Chromosome Deletion
MH  - DNA, Viral/analysis
MH  - *Enhancer Elements, Genetic
MH  - Mice
MH  - Mutation
MH  - Proviruses/*genetics
MH  - *Repetitive Sequences, Nucleic Acid
MH  - Retroviridae/*genetics
PMC - PMC251037
EDAT- 1989/10/01 00:00
MHDA- 1989/10/01 00:01
PMCR- 1989/10/01
CRDT- 1989/10/01 00:00
PHST- 1989/10/01 00:00 [pubmed]
PHST- 1989/10/01 00:01 [medline]
PHST- 1989/10/01 00:00 [entrez]
PHST- 1989/10/01 00:00 [pmc-release]
AID - 10.1128/JVI.63.10.4234-4241.1989 [doi]
PST - ppublish
SO  - J Virol. 1989 Oct;63(10):4234-41. doi: 10.1128/JVI.63.10.4234-4241.1989.