Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cDNA, p1-88, was cloned from a library constructed using rabbit liver mRNA. Sequence analysis indicates that p1-88 is highly similar (congruent to 95%) to the cDNA, p1-8, that encodes rabbit liver cytochrome P-450 1 and that had been isolated from the same library. The predicted amino acid sequence of the protein encoded by p1-88, P-450 IIC4, differs at 25 of 487 amino acids from that encoded by p1-8. P-450 IIC4 was synthesized in vitro using rabbit reticulocyte lysate primed with RNA transcribed from the coding sequence of p1-88 using a bacteriophage T7 RNA polymerase/promoter system. P-450 IIC4 reacts with two monoclonal antibodies that recognize P-450 1 and exhibits the same relative electrophoretic mobility as P-450 1. In contrast, the reactivity of a third monoclonal antibody recognizing P-450 1, 1F11, toward P-450 IIC4 synthesized in vitro is greatly diminished. The latter antibody extensively inhibits hepatic progesterone 21-hydroxylase activity and recognizes phenotypic differences among rabbits in the microsomal concentration of P-450 1. This difference in the immunoreactivity of P-450 IIC4 and P-450 1 with the 1F11 antibody suggests that P-450 IIC4 does not contribute significantly to hepatic progesterone 21-hydroxylase activity. S1 nuclease mapping demonstrates that the expression of mRNAs corresponding to p1-88 are expressed to equivalent extents in rabbits exhibiting high and low expression of mRNAs corresponding to p1-8. Thus, P-450 1 differs from the protein encoded by p1-88, in its regulation, immunoreactivity, and by inference its catalytic properties although the amino acid sequences of P-450 1 and P-450 IIC4 are highly similar (congruent to 95%).
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PMID:Characterization of a second gene product related to rabbit cytochrome P-450 1. 303 48

Interest in extra-adrenal corticosteroid synthesis has been revived by technological advances and the quest for answers to clinical problems. The cytochrome P450 21-hydroxylase converts progesterone to deoxycorticosterone, the obligatory substrate for the production of the main adrenal steroids aldosterone, cortisol and corticosterone. The rat P450 21-hydroxylase was cloned and two constructs, 21OH-5 and 21OH-6, sequenced. The constructs are similar, except that 21OH-6 has three additional major insertions of 64, 70 and 84 bp, a 3 bp deletion, and four extra base pairs immediately before the poly-A sequence. The entire coding region of 21OH-5 has 87 and 71% homology with the mouse and human 21-hydroxylase cDNA, respectively, whereas the encoded protein has 84 and 65% homology. Reverse transcriptase-polymerase chain reaction (RT-PCR) combined with Southern blot demonstrated expression of both transcripts in the kidney, aorta, liver, cerebellum, hypothalamus and brain stem, heart and cerebrum, but not the hippocampus, in addition to the adrenal. The entire coding region of 21OH-5 and the corresponding region of 21OH-6 including the three introns were cloned into pCR3 and the plasmids transiently transfected into COS-7 cells. Only 21OH-5 was translated into active protein, converting approximately 64% of 3H-progesterone to deoxycorticosterone in 2 h.
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PMID:Cloning of two alternatively spliced 21-hydroxylase CDNAs from rat adrenal. 940 81