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Expression profiles for six zebrafish genes during gonadal sex differentiation.

Jørgensen A, Morthorst JE, Andersen O, Rasmussen LJ, Bjerregaard P - Reprod. Biol. Endocrinol. (2008)

Bottom Line: The aim of this study was to determine the precise timing of expression of six genes previously suggested to be associated with sex differentiation in zebrafish.When comparing all five genes with expected sex related expression 56% show expression expected for either male or female.In zebrafish, the first significant peak in gene expression during the investigated period (2-40 dph) was dmrt1 at 10 dph which indicates involvement of this gene in the early gonadal sex differentiation of males.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Science, Systems and Models, Roskilde University, Universitetsvej 1, DK-4000 Roskilde, Denmark. annejoer@ruc.dk

ABSTRACT

Background: The mechanism of sex determination in zebrafish is largely unknown and neither sex chromosomes nor a sex-determining gene have been identified. This indicates that sex determination in zebrafish is mediated by genetic signals from autosomal genes. The aim of this study was to determine the precise timing of expression of six genes previously suggested to be associated with sex differentiation in zebrafish. The current study investigates the expression of all six genes in the same individual fish with extensive sampling dates during sex determination and -differentiation.

Results: In the present study, we have used quantitative real-time PCR to investigate the expression of ar, sox9a, dmrt1, fig alpha, cyp19a1a and cyp19a1b during the expected sex determination and gonadal sex differentiation period. The expression of the genes expected to be high in males (ar, sox9a and dmrt1a) and high in females (fig alpha and cyp19a1a) was segregated in two groups with more than 10 times difference in expression levels. All of the investigated genes showed peaks in expression levels during the time of sex determination and gonadal sex differentiation. Expression of all genes was investigated on cDNA from the same fish allowing comparison of the high and low expressers of genes that are expected to be highest expressed in either males or females. There were 78% high or low expressers of all three "male" genes (ar, sox9a and dmrt1) in the investigated period and 81% were high or low expressers of both "female" genes (fig alpha and cyp19a1a). When comparing all five genes with expected sex related expression 56% show expression expected for either male or female. Furthermore, the expression of all genes was investigated in different tissue of adult male and female zebrafish.

Conclusion: In zebrafish, the first significant peak in gene expression during the investigated period (2-40 dph) was dmrt1 at 10 dph which indicates involvement of this gene in the early gonadal sex differentiation of males.

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Tissue specific expression of ar, sox9a, dmrt1, fig α, cyp19a1a and cyp19a1b in adult zebrafish.A Tissue from male zebrafish. B Tissue from female zebrafish. L: liver, Gu: gut, S: spleen, M: muscle, Go: gonad, Gb: gall bladder, H: heart, Gi: gills, B: brain, E: eye, ÷: no DNA (water control).
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Figure 8: Tissue specific expression of ar, sox9a, dmrt1, fig α, cyp19a1a and cyp19a1b in adult zebrafish.A Tissue from male zebrafish. B Tissue from female zebrafish. L: liver, Gu: gut, S: spleen, M: muscle, Go: gonad, Gb: gall bladder, H: heart, Gi: gills, B: brain, E: eye, ÷: no DNA (water control).

Mentions: The tissue specific expression of ar, sox9a dmrt1, fig α, cyp19a1a and cyp19a1b in adult male and female zebrafish was investigated by qRT-PCR to determine whether the genes were uniformly expressed or restricted to specific tissues or sex. Investigated tissues included liver, heart, brain, spleen, muscle, gall bladder, gut, eyes, gill and gonad (Figure 8). ar was expressed in all of the ten different tissues investigated in males and females. The sox9a expression was similar in the two sexes except in gonads and gill where it was low in female fish compared to the expression in male fish indicating that this "male" gene still has a role in the adult phase. dmrt1 was expressed in spleen and gonads in both sexes, but at highest level in males. The only tissue with expression of the "female" gene fig α was female gonads. cyp19a1a and cyp19a1b were differentially expressed in different organs of male and female zebrafish, liver expression of cyp19a1a being higher in male than in female, and higher in female gonads than in male gonads. cyp19a1b expression was relatively higher in female than in male brain.


Expression profiles for six zebrafish genes during gonadal sex differentiation.

Jørgensen A, Morthorst JE, Andersen O, Rasmussen LJ, Bjerregaard P - Reprod. Biol. Endocrinol. (2008)

Tissue specific expression of ar, sox9a, dmrt1, fig α, cyp19a1a and cyp19a1b in adult zebrafish.A Tissue from male zebrafish. B Tissue from female zebrafish. L: liver, Gu: gut, S: spleen, M: muscle, Go: gonad, Gb: gall bladder, H: heart, Gi: gills, B: brain, E: eye, ÷: no DNA (water control).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2500022&req=5

Figure 8: Tissue specific expression of ar, sox9a, dmrt1, fig α, cyp19a1a and cyp19a1b in adult zebrafish.A Tissue from male zebrafish. B Tissue from female zebrafish. L: liver, Gu: gut, S: spleen, M: muscle, Go: gonad, Gb: gall bladder, H: heart, Gi: gills, B: brain, E: eye, ÷: no DNA (water control).
Mentions: The tissue specific expression of ar, sox9a dmrt1, fig α, cyp19a1a and cyp19a1b in adult male and female zebrafish was investigated by qRT-PCR to determine whether the genes were uniformly expressed or restricted to specific tissues or sex. Investigated tissues included liver, heart, brain, spleen, muscle, gall bladder, gut, eyes, gill and gonad (Figure 8). ar was expressed in all of the ten different tissues investigated in males and females. The sox9a expression was similar in the two sexes except in gonads and gill where it was low in female fish compared to the expression in male fish indicating that this "male" gene still has a role in the adult phase. dmrt1 was expressed in spleen and gonads in both sexes, but at highest level in males. The only tissue with expression of the "female" gene fig α was female gonads. cyp19a1a and cyp19a1b were differentially expressed in different organs of male and female zebrafish, liver expression of cyp19a1a being higher in male than in female, and higher in female gonads than in male gonads. cyp19a1b expression was relatively higher in female than in male brain.

Bottom Line: The aim of this study was to determine the precise timing of expression of six genes previously suggested to be associated with sex differentiation in zebrafish.When comparing all five genes with expected sex related expression 56% show expression expected for either male or female.In zebrafish, the first significant peak in gene expression during the investigated period (2-40 dph) was dmrt1 at 10 dph which indicates involvement of this gene in the early gonadal sex differentiation of males.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Science, Systems and Models, Roskilde University, Universitetsvej 1, DK-4000 Roskilde, Denmark. annejoer@ruc.dk

ABSTRACT

Background: The mechanism of sex determination in zebrafish is largely unknown and neither sex chromosomes nor a sex-determining gene have been identified. This indicates that sex determination in zebrafish is mediated by genetic signals from autosomal genes. The aim of this study was to determine the precise timing of expression of six genes previously suggested to be associated with sex differentiation in zebrafish. The current study investigates the expression of all six genes in the same individual fish with extensive sampling dates during sex determination and -differentiation.

Results: In the present study, we have used quantitative real-time PCR to investigate the expression of ar, sox9a, dmrt1, fig alpha, cyp19a1a and cyp19a1b during the expected sex determination and gonadal sex differentiation period. The expression of the genes expected to be high in males (ar, sox9a and dmrt1a) and high in females (fig alpha and cyp19a1a) was segregated in two groups with more than 10 times difference in expression levels. All of the investigated genes showed peaks in expression levels during the time of sex determination and gonadal sex differentiation. Expression of all genes was investigated on cDNA from the same fish allowing comparison of the high and low expressers of genes that are expected to be highest expressed in either males or females. There were 78% high or low expressers of all three "male" genes (ar, sox9a and dmrt1) in the investigated period and 81% were high or low expressers of both "female" genes (fig alpha and cyp19a1a). When comparing all five genes with expected sex related expression 56% show expression expected for either male or female. Furthermore, the expression of all genes was investigated in different tissue of adult male and female zebrafish.

Conclusion: In zebrafish, the first significant peak in gene expression during the investigated period (2-40 dph) was dmrt1 at 10 dph which indicates involvement of this gene in the early gonadal sex differentiation of males.

Show MeSH