Cloning of the cytochrome P450 gene, CYP4C1 from the neotropical cockroach Blaberus discoidalis and studies on potential effectors of mRNA expression /
This study is concerned with cloning of the CYP4C1 gene (CYP4C1) and investigates the hypothesis that CYP4C1 is regulated by non-endocrine factors that induce expression of cytochrome P450 fatty acid mRNAs in vertebrates. The possibility that the hypertrehalosemic hormone from the cockroach, Blaberu...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=727726161&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | This study is concerned with cloning of the CYP4C1 gene (CYP4C1) and investigates the hypothesis that CYP4C1 is regulated by non-endocrine factors that induce expression of cytochrome P450 fatty acid mRNAs in vertebrates. The possibility that the hypertrehalosemic hormone from the cockroach, Blaberus discoidalis (Bld-HrTH) regulates mRNA expression of a CYP4 in a related species of cockroach was also investigated. Data on Bld-HrTH induction of CYP4 mRNA in the cockroach Leucophea. maderae was ambiguous but implied that Bld-HrTH induces an unprocessed CYP4 transcript under the temporal and dosage conditions necessary for maximal induction of CYP4C1 mRNA by Bld-HrTH in B. discoidalis. Clofibric acid, ethanol, and acetone were administered at doses and times commensurate with those that induce CYP transcripts of fatty acid hydroxylases expressed in vertebrates. Only administration of acetone under acute conditions showed an induction of CYP4C1 mRNA, a response that could be a non-specific stress effect. Thus, there was no clear demonstration that chemicals that induce cytochrome P450 fatty acid hydroxylase mRNAs in vertebrates also specifically induce CYP4C1 mRNA in B. discoidalis. Clofibric acid caused a head dependant repression of CYP4C1 mRNA under conditions of acute administration implying that it causes the release of a head dependant repressor of CYP4C1 transcript previously postulated (Lu, 1995). Ethanol also demonstrated repressive effects when administered chronically and appeared to block the induction of CYP4CI mRNA associated with the process of decapitation. Studies on CYP4C1 showed that it is part of a large genome, polymorphic, approximately 25 kilobases long and probably present only once in the genome. Isolation of a 5' flanking region revealed little similarity in sequence with the 5' flanking regions of cytochrome P450 genes encoding other P450 fatty acid hydroxylases. One intron in the 5' untranslated region and ten introns were mapped within the CYP4C1 coding block. Of the ten introns, within the coding block, four correspond in position to the four introns of CYP4D2 expressed in Drosophila melanogaster and one corresponds to one of the twelve introns of CYP4A1 expressed in rats. |
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| Item Description: | In title, numerals are used. Vita. "Major Subject: Biology". |
| Physical Description: | xi, 125 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 108-124). |