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Characterization of gonadal transcriptomes from Nile tilapia (Oreochromis niloticus) reveals differentially expressed genes.

Tao W, Yuan J, Zhou L, Sun L, Sun Y, Yang S, Li M, Zeng S, Huang B, Wang D - PLoS ONE (2013)

Bottom Line: Of these, 259 genes were found to be specifically expressed in XY gonads, and 69 were found to be specific to XX gonads.Totally, 187 XX- and 1,358 XY-enhanced genes were identified, and 2,978 genes were found to be co-expressed in XX and XY gonads.Both estrogen and androgen receptors were found to be expressed in XX gonads, but only estrogen receptors were expressed in XY gonads at 5 dah.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing, PR China.

ABSTRACT
Four pairs of XX and XY gonads from Nile tilapia were sequenced at four developmental stages, 5, 30, 90, and 180 days after hatching (dah) using Illumina Hiseq(TM) technology. This produced 28 Gb sequences, which were mapped to 21,334 genes. Of these, 259 genes were found to be specifically expressed in XY gonads, and 69 were found to be specific to XX gonads. Totally, 187 XX- and 1,358 XY-enhanced genes were identified, and 2,978 genes were found to be co-expressed in XX and XY gonads. Almost all steroidogenic enzymes, including cyp19a1a, were up-regulated in XX gonads at 5 dah; but in XY gonads these enzymes, including cyp11b2, were significantly up-regulated at 90 dah, indicating that, at a time critical to sex determination, the XX fish produced estrogen and the XY fish did not produce androgens. The most pronounced expression of steroidogenic enzyme genes was observed at 30 and 90 dah for XX and XY gonads, corresponding to the initiation of germ cell meiosis in the female and male gonads, respectively. Both estrogen and androgen receptors were found to be expressed in XX gonads, but only estrogen receptors were expressed in XY gonads at 5 dah. This could explain why exogenous steroid treatment induced XX and XY sex reversal. The XX-enhanced expression of cyp19a1a and cyp19a1b at all stages suggests an important role for estrogen in female sex determination and maintenance of phenotypic sex. This work is the largest collection of gonadal transcriptome data in tilapia and lays the foundation for future studies into the molecular mechanisms of sex determination and maintenance of phenotypic sex in non-model teleosts.

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Five types of genes in XX and XY transcriptomes of tilapia gonads.A hierarchical clustering of differentially expressed transcripts (FDR≤10−2 and /log2 (XX_RPKM/XY_RPKM)/≥1) generated five types of genes. “SEGs” indicate genes specific to either XX or XY. “ND-SEGs” indicate SEGs that did not meet statistical criteria. “XX-DIGs” indicate XX differentially expressed genes. “XY-DIGs” indicate XY differentially expressed genes. “COGs” indicate XX and XY co-expressed genes.
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pone-0063604-g003: Five types of genes in XX and XY transcriptomes of tilapia gonads.A hierarchical clustering of differentially expressed transcripts (FDR≤10−2 and /log2 (XX_RPKM/XY_RPKM)/≥1) generated five types of genes. “SEGs” indicate genes specific to either XX or XY. “ND-SEGs” indicate SEGs that did not meet statistical criteria. “XX-DIGs” indicate XX differentially expressed genes. “XY-DIGs” indicate XY differentially expressed genes. “COGs” indicate XX and XY co-expressed genes.

Mentions: The global analysis of the number of genes for each transcriptome showed that more genes were expressed in the XY than in the XX gonads at every developmental stage examined (Figure 3). There were 9,549, 17,492, 8,652, and 10,030 COGs expressed in gonads at 5, 30, 90, and 180 dah, respectively; 30 dah constituted the largest change in magnitude across the four developmental stages. There were 91, 0, 37, and 10 XX-SEGs and 296, 3, 392, and 187 XY-SEGs at 5, 30, 90, and 180 dah, respectively. The number of SEGs was negatively correlated with the number of COGs expressed at all four stages. While the numbers of XX-DIGs at 5, 30, 90, and 180 dah were 1,394, 512, 3,057, and 3,653, respectively, the corresponding numbers for XY DIGs were: 4,882, 2,254, 6,065, and 5,412, respectively. Overall, more SEGs and DIGs were observed in XY gonads. A simple comparison of the scatter plots of the gene expression profiles at each developmental stage also revealed that there were more up-regulated genes in XY (red plots) than in XX (green plots) at all four developmental stages (Figure 4), which is consistent with the enhanced SEGs and DIGs observed in XY gonads (Figure 3). Among the four developmental stages, the most substantial differences between the two sexes were observed at 180 dah, followed by 90, 5, and 30 dah in decreasing order (Figure 3 and Figure 4). When the gene expression profiles of the same sex at different stages were compared, the 90 and 180 dah groups were found to share the most similarity in expression profile (Figure S1).


Characterization of gonadal transcriptomes from Nile tilapia (Oreochromis niloticus) reveals differentially expressed genes.

Tao W, Yuan J, Zhou L, Sun L, Sun Y, Yang S, Li M, Zeng S, Huang B, Wang D - PLoS ONE (2013)

Five types of genes in XX and XY transcriptomes of tilapia gonads.A hierarchical clustering of differentially expressed transcripts (FDR≤10−2 and /log2 (XX_RPKM/XY_RPKM)/≥1) generated five types of genes. “SEGs” indicate genes specific to either XX or XY. “ND-SEGs” indicate SEGs that did not meet statistical criteria. “XX-DIGs” indicate XX differentially expressed genes. “XY-DIGs” indicate XY differentially expressed genes. “COGs” indicate XX and XY co-expressed genes.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3643912&req=5

pone-0063604-g003: Five types of genes in XX and XY transcriptomes of tilapia gonads.A hierarchical clustering of differentially expressed transcripts (FDR≤10−2 and /log2 (XX_RPKM/XY_RPKM)/≥1) generated five types of genes. “SEGs” indicate genes specific to either XX or XY. “ND-SEGs” indicate SEGs that did not meet statistical criteria. “XX-DIGs” indicate XX differentially expressed genes. “XY-DIGs” indicate XY differentially expressed genes. “COGs” indicate XX and XY co-expressed genes.
Mentions: The global analysis of the number of genes for each transcriptome showed that more genes were expressed in the XY than in the XX gonads at every developmental stage examined (Figure 3). There were 9,549, 17,492, 8,652, and 10,030 COGs expressed in gonads at 5, 30, 90, and 180 dah, respectively; 30 dah constituted the largest change in magnitude across the four developmental stages. There were 91, 0, 37, and 10 XX-SEGs and 296, 3, 392, and 187 XY-SEGs at 5, 30, 90, and 180 dah, respectively. The number of SEGs was negatively correlated with the number of COGs expressed at all four stages. While the numbers of XX-DIGs at 5, 30, 90, and 180 dah were 1,394, 512, 3,057, and 3,653, respectively, the corresponding numbers for XY DIGs were: 4,882, 2,254, 6,065, and 5,412, respectively. Overall, more SEGs and DIGs were observed in XY gonads. A simple comparison of the scatter plots of the gene expression profiles at each developmental stage also revealed that there were more up-regulated genes in XY (red plots) than in XX (green plots) at all four developmental stages (Figure 4), which is consistent with the enhanced SEGs and DIGs observed in XY gonads (Figure 3). Among the four developmental stages, the most substantial differences between the two sexes were observed at 180 dah, followed by 90, 5, and 30 dah in decreasing order (Figure 3 and Figure 4). When the gene expression profiles of the same sex at different stages were compared, the 90 and 180 dah groups were found to share the most similarity in expression profile (Figure S1).

Bottom Line: Of these, 259 genes were found to be specifically expressed in XY gonads, and 69 were found to be specific to XX gonads.Totally, 187 XX- and 1,358 XY-enhanced genes were identified, and 2,978 genes were found to be co-expressed in XX and XY gonads.Both estrogen and androgen receptors were found to be expressed in XX gonads, but only estrogen receptors were expressed in XY gonads at 5 dah.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing, PR China.

ABSTRACT
Four pairs of XX and XY gonads from Nile tilapia were sequenced at four developmental stages, 5, 30, 90, and 180 days after hatching (dah) using Illumina Hiseq(TM) technology. This produced 28 Gb sequences, which were mapped to 21,334 genes. Of these, 259 genes were found to be specifically expressed in XY gonads, and 69 were found to be specific to XX gonads. Totally, 187 XX- and 1,358 XY-enhanced genes were identified, and 2,978 genes were found to be co-expressed in XX and XY gonads. Almost all steroidogenic enzymes, including cyp19a1a, were up-regulated in XX gonads at 5 dah; but in XY gonads these enzymes, including cyp11b2, were significantly up-regulated at 90 dah, indicating that, at a time critical to sex determination, the XX fish produced estrogen and the XY fish did not produce androgens. The most pronounced expression of steroidogenic enzyme genes was observed at 30 and 90 dah for XX and XY gonads, corresponding to the initiation of germ cell meiosis in the female and male gonads, respectively. Both estrogen and androgen receptors were found to be expressed in XX gonads, but only estrogen receptors were expressed in XY gonads at 5 dah. This could explain why exogenous steroid treatment induced XX and XY sex reversal. The XX-enhanced expression of cyp19a1a and cyp19a1b at all stages suggests an important role for estrogen in female sex determination and maintenance of phenotypic sex. This work is the largest collection of gonadal transcriptome data in tilapia and lays the foundation for future studies into the molecular mechanisms of sex determination and maintenance of phenotypic sex in non-model teleosts.

Show MeSH