Limits...
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.

Show MeSH
The levels of expression of 17 steroidogenic enzyme genes, three estrogen receptor genes (esr1, esr2a, and esr2b) and two androgen receptor genes (ar1 and ar2) in XX and XY gonads of tilapia at 5, 30, 90, and 180 dah.Numbers within the figure indicate RPKM values.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3643912&req=5

pone-0063604-g005: The levels of expression of 17 steroidogenic enzyme genes, three estrogen receptor genes (esr1, esr2a, and esr2b) and two androgen receptor genes (ar1 and ar2) in XX and XY gonads of tilapia at 5, 30, 90, and 180 dah.Numbers within the figure indicate RPKM values.

Mentions: Genes involved in sex steroid synthesis mostly showed higher expression levels in XX gonads than in XY gonads at 5 dah. The exceptions included star1, cyp17a1, hsd11b2, esr2a, and esr2b. The total and average RPKM of the listed 17 steroidogenic enzyme genes were 84 and 5 for XX, and 27 and 2 for XY gonads at 5 dah, respectively (Table 3). We observed higher expression levels of steroidogenic enzyme genes such as star2, cyp11a1, cyp17a2, hsd3b1, hsd17b8, hsd17b12a2, hsd17b14, cyp19a1a, and cyp19a1b in XX than in XY gonads at 5 dah (Figure 5). However, cyp11b2 (encoding the key enzyme 11β-hydroxylase for androgen production in tilapia) was not detected in either XX or XY gonads at 5 dah. From 5 to 30 dah, expression of steroidogenic enzyme genes in both XX and XY gonads underwent an exponential increase, with the total and average reaching 1,728 and 102 for XX and 683 and 40 for XY, respectively. Cyp19a1a was the most dramatically differentially expressed gene among these 17 genes between 5 and 30 dah. However, the expression profiles of these genes were completely reversed at 90 and 180 dah. During this period, almost all genes were up-regulated in the XY gonads and down-regulated in the XX gonads; with the total and average reaching 3,866 and 227 at 90 dah and 4,772 and 281 at 180 dah for XY gonads, respectively. These numbers diminished to 771 and 45 at 90 dah, and 837 and 49 at 180 dah for XX gonads, respectively. Hsd17b1 was the most dramatically differentially expressed gene among these 17 steroidogenic enzyme genes at 90 and 180 dah. RPKMs of star1, star2, cyp11a1, cyp17a1, cyp17a2, and hsd3b1 were higher than 200, and several exceeded 1,000, in XY gonads, but only a few estrogen-producing enzyme genes, such as hsd3b2 and cyp19a1a, displayed moderate expression in XX gonads. At these two stages, expression of cyp19a1b was down regulated, with RPKMs less than 15 even in XX gonads. Unexpectedly, hsd17bs exhibited low levels of expression (with RPKM no more than 30) in both XX and XY gonads at all four developmental stages. However, hsd17b12a1 showed a relatively high level of expression at 30 and 180 dah in XX gonads, and hsd17b12a2 showed a relatively high level of expression at 90 dah in XY gonads.


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)

The levels of expression of 17 steroidogenic enzyme genes, three estrogen receptor genes (esr1, esr2a, and esr2b) and two androgen receptor genes (ar1 and ar2) in XX and XY gonads of tilapia at 5, 30, 90, and 180 dah.Numbers within the figure indicate RPKM values.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0063604-g005: The levels of expression of 17 steroidogenic enzyme genes, three estrogen receptor genes (esr1, esr2a, and esr2b) and two androgen receptor genes (ar1 and ar2) in XX and XY gonads of tilapia at 5, 30, 90, and 180 dah.Numbers within the figure indicate RPKM values.
Mentions: Genes involved in sex steroid synthesis mostly showed higher expression levels in XX gonads than in XY gonads at 5 dah. The exceptions included star1, cyp17a1, hsd11b2, esr2a, and esr2b. The total and average RPKM of the listed 17 steroidogenic enzyme genes were 84 and 5 for XX, and 27 and 2 for XY gonads at 5 dah, respectively (Table 3). We observed higher expression levels of steroidogenic enzyme genes such as star2, cyp11a1, cyp17a2, hsd3b1, hsd17b8, hsd17b12a2, hsd17b14, cyp19a1a, and cyp19a1b in XX than in XY gonads at 5 dah (Figure 5). However, cyp11b2 (encoding the key enzyme 11β-hydroxylase for androgen production in tilapia) was not detected in either XX or XY gonads at 5 dah. From 5 to 30 dah, expression of steroidogenic enzyme genes in both XX and XY gonads underwent an exponential increase, with the total and average reaching 1,728 and 102 for XX and 683 and 40 for XY, respectively. Cyp19a1a was the most dramatically differentially expressed gene among these 17 genes between 5 and 30 dah. However, the expression profiles of these genes were completely reversed at 90 and 180 dah. During this period, almost all genes were up-regulated in the XY gonads and down-regulated in the XX gonads; with the total and average reaching 3,866 and 227 at 90 dah and 4,772 and 281 at 180 dah for XY gonads, respectively. These numbers diminished to 771 and 45 at 90 dah, and 837 and 49 at 180 dah for XX gonads, respectively. Hsd17b1 was the most dramatically differentially expressed gene among these 17 steroidogenic enzyme genes at 90 and 180 dah. RPKMs of star1, star2, cyp11a1, cyp17a1, cyp17a2, and hsd3b1 were higher than 200, and several exceeded 1,000, in XY gonads, but only a few estrogen-producing enzyme genes, such as hsd3b2 and cyp19a1a, displayed moderate expression in XX gonads. At these two stages, expression of cyp19a1b was down regulated, with RPKMs less than 15 even in XX gonads. Unexpectedly, hsd17bs exhibited low levels of expression (with RPKM no more than 30) in both XX and XY gonads at all four developmental stages. However, hsd17b12a1 showed a relatively high level of expression at 30 and 180 dah in XX gonads, and hsd17b12a2 showed a relatively high level of expression at 90 dah in XY gonads.

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