Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:2.3.1.28 (
chloramphenicol acetyltransferase
)
5,100
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The nucleotide sequence of the pol-env intergenic region of two isolates of caprine arthritis-encephalitis virus (CAEV) was determined. Two open reading frames (orfs) were identified, designated Q and S by homology with visna virus. CAEV
orf
S is a single exon encoding a deduced 87-amino acid gene product sharing 36 amino acid identities with the visna trans-acting transcriptional activator (Tat). Ten of these identities comprise a conserved CGCRLCNPGW sequence similar to a cysteine-rich domain essential for trans-activation by human immunodeficiency virus Tat. To determine if transcription promoted by the CAEV long terminal repeat (LTR) could be stimulated in CAEV-infected goat synovial membrane cells, a plasmid (pCAE-
CAT
) expressing bacterial
chloramphenicol acetyltransferase
(
CAT
) under control of the CAEV LTR was transfected into uninfected and infected cells. Sixfold enhancement of
CAT
activity was observed in infected cells using 100 ng of transfected plasmid. To determine if the pol-env region encodes a gene product which trans-activates the CAEV LTR, goat synovial membrane cells were cotransfected with pCAE-
CAT
and pRSV-1.9, a plasmid expressing the pol-env region under control of the Rous sarcoma virus LTR. Results indicated that the CAEV genome encodes a tat gene product attributable to
orf
S.
...
PMID:Genetic structure of the pol-env region of the caprine arthritis-encephalitis lentivirus genome. 184 32
We previously described use of the human parvovirus, adeno-associated virus (AAV), as a vector for transient expression in mammalian cells of the gene for
chloramphenicol acetyltransferase
(
CAT
). In the AAV vector, pTS1, the
CAT
gene is expressed under the control of the major AAV promoter p40. This promoter is embedded within the carboxyl-terminal region of an open reading frame (
orf
-1) which codes for a protein (rep) required for AAV DNA replication. We show here that the rep product has additional trans-acting properties to regulate gene expression. First, deletion or frame-shift mutations in
orf
-1, which occurred far upstream of p40, increased expression of
CAT
in human 293 (adenovirus-transformed) cells. This increased
CAT
expression was abolished when such mutant AAV vectors were transfected into 293 cells together with a second AAV vector which could supply the wild-type AAV rep product in trans. Thus, an AAV rep gene product was a negative regulator, in trans, of expression of
CAT
in uninfected 293 cells. In adenovirus-infected 293 cells, the function of the AAV rep product was more complex, but in some cases, it appeared to be a trans activator of the expression from p40. In HeLa cells, only trans activation by rep was seen in the absence or presence of adenovirus. Neither activation nor repression by the rep product required replication per se of the AAV vector DNA. Thus, trans-acting negative or positive regulation of gene expression by the AAV rep gene is modulated by factors in the host cell and by the helper adenovirus.
...
PMID:Negative and positive regulation in trans of gene expression from adeno-associated virus vectors in mammalian cells by a viral rep gene product. 349 Dec 93
