Studies On The Expression Of A Few Kinds Of CYP Genes In The Different Phases Of Gonad Development In Zebrafish

Zebrafish(Danio rerio，Zebrafish)is an ideal model organism in the developmental biology and geneticsresearch. It has some incomparable advantages which fruit flies, mice and other model organisms has not suchas high fecundity,external fertilization, transparent embryos,short generation time, can track the wholeprocess of embryonic development, therefore it is especially suitable for the study of the development and sexdetermination and differentiation related genes expression and function.Cytochrome P450(CYP450) super gene family is a kind of gene which coding the enzyme familieswhich participate in some endogenous substances (e.g., hormones, cholesterol) and exogenous substances’(e.g., drugs, environmental compounds) metabolic process. The CYP450enzyme encoding by CYP450genebelongs to the hemoglobin-a kind of heme auxiliary base cytochrome protease superfamily and they widelyexists in the organism.There are94kinds of CYP450genes in zebrafish which distributed in18gene families,and these genefamilies also exist in mammals. There are32CYP gene in CYP5-CYP51gene family which homology withhuman beings and associated with hormone metabolism enzymes in organisms, such as CYP11, CYP17,CYP19, CYP21,CYP51respectively encoded cholesterol side-chain cleavage P450scc,17α-hydroxylaseenzyme/C17,20lyase, aromatase, steroid-21hydroxylase, lanosterol14α-demethylase;these enzymes areclosely related in hormones biological metabolic.In this study,we judged the different phases of gonad development of zebrafish by paraffin section. Thenwe choose three phases: the stage before sexual maturity, sexual maturity stage and the stage after sexualmaturity as study objects to study the expression of CYP11,CYP17,CYP19,CYP21,CYP51.We used fourtissues: ovary,testis, muscle and brain to found the tissue distribution profile. The tissue distribution profileresult showed that expect for CYP19a didn’t expressed in the muscle the rest of the several genes are expressedin these four kinds of tissues, the maximal expression level of CYP11a1gene was in the ovary, higher in thetestis and the minimal was in the brain; the maximal expression level of CYP17a1gene was in the muscle,higher in the testis and the minimal was in the brain; the maximal expression level of CYP17a2gene was inthe testis, higher in the muscle and the minimal was in the brain; the maximal expression level of CYP19agene was in the ovary, higher in the testis, the minimal was in the brain, no expression in the muscle; themaximal expression level of CYP19b gene was in the brain,higher in the testis, the minimal was in the ovary;the maximal expression level of CYP21gene was in the muscle,higher in the testis, the minimal was in theovary; the maximal expression level of CYP51gene was in the testis,higher in the brain, the minimal was inthe ovary.The result of Real-time PCR showed that the expression of CYP11a1gene in the three different phases ofovary development was reduced first then increased and the minimal expression level was at sexual maturityphase; the expression of CYP11a1gene in the three different phases of testis development was increased firstthen reduced and the maximal expression level was at the sexual maturity phase. The expression of CYP17a1gene in the three different phases of ovary development was reduced first then increased and the minimalexpression level was at the sexual maturity phase; the expression of CYP17a1gene in the three differentphases of testis development was same as the expression at the ovary. The expression of CYP17a2gene in thethree different phases of ovary development was reduced in all the three phase and the peak was at the phasebefore sexual maturity; the expression of CYP17a2gene in the three different phases of testis development wasincreased in all the phases and the minimal expression level was at the the phase before sexual maturity.The expression of CYP19a gene in the three different phases of ovary development was increased in all the phasesand the minimal expression level was at the phase before sexual maturity; the expression of CYP19a gene inthe three different phases of testis development was reduced in all the phases and the peak expression levelwas in the the phase before sexual maturity.The expression of CYP19b gene in the three different phases of theovary was the same as the expression in the testis, the expression level was in peak at the phase before sexualmaturity.The expression of CYP21gene in the three different phases of ovary development was reduced in allthe phases and the peak was at the phase before sexual maturity; the expression of CYP21gene in the threedifferent phases of testis development was reduced first and then increased,the minimal expression level wasat the sexual maturity.The expression of CYP51gene in the three different phases of ovary development wasreduced in all the phases and the peak was at the phase before sexual maturity; the expression of CYP51gene inthe three different phases of testis development was reduced first and then increased,the minimal expressionlevel was at the sexual maturity.