Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have analyzed the cis-acting regulatory sequences of the Drosophila melanogaster Rh2 gene that encodes the protein component of a rhodopsin which is expressed in ocellar photoreceptor cells. DNA fragments containing the start point of transcription of the Rh2 gene were fused to either the Escherichia coli chloramphenicol acetyltransferase (CAT) or lacZ (beta-galactosidase) genes and introduced into the Drosophila germline by P-element-mediated transformation. Expression of the E. coli genes was then used to assay the ability of various sequences from the Rh2 gene to confer upon the indicator genes the Rh2 pattern of expression. Fragments containing between 4.3 kb and 183 bp upstream of the start of transcription plus the first 32 bp of the 5'-untranslated leader were found to result in nearly identical levels of head-specific CAT expression. Deletion of Rh2 sequences distal to position -112 bp resulted in loss of detectable CAT expression from these Rh2/CAT fusion constructs. We have, therefore, defined a region essential for head-specific expression of the Rh2 gene to a region extending from -183 to -112. We have determined the DNA sequence of the Rh2 promoter from -448 to +32 and have found an 11-bp sequence which is also present in the upstream flanking sequences of two other photoreceptor-specific genes (ninaE and ninaC). By histochemical staining of beta-galactosidase expressed under the control of the Rh2 promoter and by analyzing the effect of the ocelliless mutation on the expression of an Rh2/CAT fusion gene, we have been able to demonstrate that this promoter is active in ocelli.
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PMID:Analysis of the promoter of the Rh2 opsin gene in Drosophila melanogaster. 297 15

Drosophila promoter fusion stocks containing a chloramphenicol acetyltransferase (CAT) reporter gene fused to a 2.8 kb DNA fragment from the Rh1 opsin promoter were carotenoid deprived from egg to adult, and then adults were replaced by feeding carrot juice. CAT activity, determined by radiometric assay, was low in deprived flies; it increased rapidly during the first 3 days of replacement and then declined back to the control level. Retinoic acid increased peak CAT activity as much as carrot juice and more than beta-carotene, all-trans retinol or all-trans retinal. These findings suggest that vitamin A serves not only as rhodopsin's chromophore but also influences Rh1 opsin gene transcription. Three stocks with various deletions in the Rh1 opsin promoter lacked the carrot juice-dependent elevation of CAT activity. All three deletions include the region from -701 to -488, suggesting that this region may contain a vitamin A-responsive DNA sequence.
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PMID:Increased expression of chloramphenicol acetyltransferase by carotenoid and retinoid replacement in Drosophila opsin promoter fusion stocks. 840 84