Avtor/Urednik		Fon-Tacer, Klementina
Naslov		Tkivno-specifično uravnavanje izražanja holesterogenih genov
Prevedeni naslov		Tissue-specific regulation of cholesterogenic genes expression
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Medicinska fakulteta
Leto izdaje		2002
Obseg		str. 116
Jezik		slo
Abstrakt		Lanosterol 14alpha-demethylase is the only member of the cytochrome P450 gene superfamily involved in the housekeeping pathway of cholesterol biosynthesis. CYP51 converts lanosterol to FF-MAS, meiosis activating sterol, isolated from human follicular fluid. FFMAS and its reduced form T-MAS (meiosis activating sterol, isolated from bull testis) are postsqualene cholesterol intermediates, accumulating in mammalian gonads. FF-MAS and T-MAS are able to trigger reinitiation of oocyte meiosis in in vitro assay. In mammals, CYPS 1 is expressed in all tissues with the highest level in testis, precisely in haploid male germ cells, due to the appearance of shorter testis-specific transcripts. Cholesterol biosynthesis is precisely regulated through cholesterol negative feedback loop by transcription factors SREBP (sterol responsive element binding protein). Expression of CYP51 gene is regulated through sterol/SREBP dependent mechanism as well as through mechanism dependent on cAMP/CREMtau. In haploid male germ cells, cholesterol-independent cAMP/CREMtau dependent mechanism predominates. We investigated the expression of cholesterogenic genes in mouse and rat testis. In rat testis, genes encoding enzymes involved in MAS synthesis (HMG CoA-synthase, HMG CoA-reductase, FPP synthase, squalene synthase and CYP51) are expressed at higher level compared to genes encoding enzymes responsible for MAS conversion toward cholesterol (sterol C4-methyl oxidase, sterol delta 7-reductase). Expression of pre-MAS genes in testis is upregulated during sexual development of the rat. Expression level of post-MAS genes in rat testis is low and even decreases during maturation of the rat. Expression of cholesterogenic genes in testis is, in contrast to liver, discordant. (Abstract truncated at 2000 characters).
Deskriptorji		CHOLESTEROL CYTOCHROME P-450 LANOSTEROL TRANSFORMATION, GENETIC GENE EXPRESSION MICE RATS PLASMIDS ELECTROPHORESIS, AGAR GEL CELL LINE TRANSFECTION RNA, MESSENGER BLOTTING, WESTERN BASE SEQUENCE TESTIS GENE LIBRARY