High impact information on Cyp4e3

• Waters and colleagues recently suggested [Waters, L. C., Zelhof, A. C., Shaw, B. J. & Ch'ang, L.-Y. (1992) Proc. Natl. Acad. Sci. USA 89, 4855-4859] that an insertion of a long terminal repeat of transposable element 17.6 into the 3' untranslated region of a P450 gene leads to susceptibility to the insecticide DDT in Drosophila melanogaster [1].
• Furthermore, analysis of c/ebp beta-deficient mice shows that mutant animals are defective in expression of a murine CYP2D5 homolog in hepatic cells, confirming the selective ability of C/EBP beta to activate this liver-specific P-450 gene in vivo [2].
• Immunoblot analyses of mature and regressed corpora lutea indicated a parallel expression of Ad4BP and side-chain cleavage P-450, and both proteins significantly decreased in the regressed tissues [3].
• Ad4BP, a zinc finger DNA-binding protein, was identified as a transcription factor regulating steroidogenic P-450 genes in a cAMP-dependent manner [3].
• One functional CYP51 gene and two processed pseudogenes, which are the first examples of intronless pseudogenes within the P450 superfamily, have been mapped to three different human chromosomes [4].

Biological context of Cyp4e3

• Cytochrome P450 gene clusters in Drosophila melanogaster [5].
• We provide here a list of 481 P450 genes and 22 pseudogenes, plus all accession numbers that have been reported as of October 18, 1995 [4].
• Formation of 2-bromoacrolein (2BA) from tris(2,3-dibromopropyl)phosphate (Tris-BP) by cytochrome P450 (cyt. P450) activity is most likely responsible for the high mutagenicity of Tris-BP for bacteria in vitro when rat liver microsomes are used for metabolic activation [6].
• The expression of insecticide resistance-related cytochrome P450 forms is regulated by molting hormone in Drosophila melanogaster [7].
• These strains contain chromosomes 1 and 2 of the DDT-resistant stock Oregon R(R) which exhibits a high constitutive level of cytochrome P450 [8].

Associations of Cyp4e3 with chemical compounds

• The concentrations of these labdane diterpenes required to elicit a 50% inhibition of the cytochrome P-450 dependent steroid hydroxylase activity in the insect tissues ranged from approximately 5 x 10(-6) to 5 x 10(-4) M [9].
• Effects of the adenylate cyclase activator forskolin and its inactive derivative 1,9-dideoxyforskolin on insect cytochrome P-450 dependent steroid hydroxylase activity [9].
• P450-dependent bioactivation of Tris-BP [6].
• Addition of NADPH enhanced 3-hydroxyretinal formation and the presence of carbon monoxide inhibited it, suggesting that hydroxylation at the C3 position of retinal occurred via the monooxygenase activity of cytochrome P-450 [10].
• The role of the 20HE in the regulation of cytochrome P450-mediated insecticide resistance has been proposed [7].

Analytical, diagnostic and therapeutic context of Cyp4e3

• Twelve cytochrome P450 cDNA fragments were cloned from Drosophila melanogaster by reverse transcriptase/PCR (RT/PCR) using degenerate oligonucleotide primers [5].
• P450 superfamily: update on new sequences, gene mapping, accession numbers and nomenclature [4].

References