Analyzing the gonadal transcriptome of the frog Hoplobatrachus rugulosus to identify genes involved in sex development

Pan

et al. 2022

IJMS

In China, the Cranoglanis bouderius is classified as a national class II-protected animal. The development of C. bouderius populations has been affected by a variety of factors over the past few decades, with severe declines occurring. Considering the likelihood of continued population declines of the C. bouderius in the future, it is critical to investigate the currently unknown characteristics of gonadal differentiation and sex-related genes for C. bouderius conservation. In this study, the Illumina sequencing platform was used to sequence the gonadal transcriptome of the C. bouderius to identify the pathways and genes related to gonadal development and analyze the expression differences in the gonads. A total of 12,002 DEGs were identified, with 7220 being significantly expressed in the ovary and 4782 being significantly expressed in the testis. According to the functional enrichment results, the cell cycle, RNA transport, apoptosis, Wnt signaling pathway, p53 signaling pathway, and prolactin signaling pathway play important roles in sex development in the C. bouderius. Furthermore, the sequence characterization and evolutionary analysis revealed that AMH, DAX1, NANOS1, and AR of the C. bouderius are highly conserved. Specifically, the qRT-PCR results from various tissues showed significant differences in AMH, DAX1, NANOS1, and AR expression levels in the gonads of both sexes of C. bouderius. These analyses indicated that AMH, DAX1, NANOS1, and AR may play important roles in the differentiation and development of C. bouderius gonads. To our best knowledge, this study is the first to analyze the C. bouderius gonadal transcriptome and identify the structures of sex-related genes, laying the foundation for future research.

Section: Discussionsupporting

confidence: 92%

Gonadal Transcriptome Analysis and Sequence Characterization of Sex-Related Genes in Cranoglanis bouderius

Pan

et al. 2022

IJMS

“…The CYP17 mRNA expression trend seen in H. rugulosus in this study was similar to a recent study in H. rugulosus, in which the expression of CYP17 mRNA was higher in males than in females at 3 and 15 months postmetamorphosis (Tang et al, 2021), and in L. mRNA was also upregulated in the ovotestis of ZW transgenic G.…”

Section: Discussionsupporting

confidence: 90%

“…In comparison, the CYP19 mRNA level in intersex and male gonads were lower than in female gonads. The CYP19 mRNA expression level correlated with a previous study in H. rugulosus, in which the expression of CYP19 mRNA was higher in females than males at the age of 3-and 15-months postmetamorphosis (Tang et al, 2021). Similarly, in G. rugosa the expression of CYP19 mRNA was observed during ovarian differentiation and the level was much higher in the developing ovary that contained immature oocytes (Kato et al, 2004).…”

Section: Discussionsupporting

confidence: 85%

“…The gonadal gene expression levels were different between sexes of H. rugulosus of 3‐ and 15‐months‐old frogs. The expression level of CYP3α , CYP17α , HSD3β , HSD11β1 , SOX2 , SOX9 , and SOX30 were higher in males than in females, whereas the expression level of SOAT , CYP19α , HSD17β12 , and HSPA1S were higher in females than in males (Tang et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Steroidogenic potential of the gonad during sex differentiation in the rice field frog Hoplobatrachus rugulosus (Anura: Dicroglossidae)

et al. 2023

Prior studies demonstrated that gonadal differentiation in the rice field frog, Hoplobatrachus rugulosus, was of an undifferentiated type since all individuals had ovaries at complete metamorphosis. However, the steroidogenic potential of the gonad is still unknown. In this study, H. rugulosus were obtained by stimulating fertilization in the laboratory under natural light and temperature conditions. The gonads were collected and their steroidogenic potential was evaluated by determining the expression level of messenger RNA (mRNA) encoding for cytochrome P450 17‐hydroxylase/C17–20 lyase (CYP17) and cytochrome P450 aromatase (CYP19) using quantitative real‐time RT‐PCR and the localization of CYP17 mRNA in tissues by in situ hybridization. The CYP17 mRNA levels in males at 4–11 weeks postmetamorphosis were higher than in female and intersex gonads. This corresponded to their localization in the gonadal tissues, where CYP17 signals were specifically detected in the Leydig cells of the testis at 5–16 weeks postmetamorphosis but was undetectable in all ovary samples. The CYP19 mRNA levels in females at 4–11 weeks postmetamorphosis was higher than in male and intersex gonads, which corresponded with gonadal development, indicating the potential steroidogenic function of the ovary. Based on the present results, the role of CYP17 and CYP19 mRNA in sex differentiation in H. rugulosus may occur after gonadal sex differentiation and the steroidogenic potential of the gonads exhibited a sexual dimorphic pattern. These results provide a crucial basis for further research on the developmental biology in anuran species.

“…In order to understand the molecular mechanism of sex reversal in R. dybowskii , transcriptome analysis was performed, and only 117 DEGs were screened between male and pseudo-male testes, which is much lower than the number of DEGs screened from testis and ovary in similar studies [ 35 , 36 ]. DEGs up to 35539 were found between the testes and ovaries of 15-month-old Hoplobatrachus rugulosus , an endangered frog from southern China [ 36 ], and a total of 13,448 DEGs were found between stage III ovaries and testes of Trachinotus ovatus [ 35 ]. Ye et al [ 37 ] screened 1893 DEGs at the transcript level between the ovaries of females and the testes of pseudo-males in the sex reversal of Cynoglossus semilaevis .…”

Section: Discussionmentioning

confidence: 99%

Testicular Transcriptome of Males and Pseudo-Males Provides Important New Insight into Sex Reversal of Rana dybowskii

Cui

et al. 2022

Animals

Rana dybowskii (R. dybowskii) is an ecological species found in China, Japan, Korea, and Russia. Like most amphibians, R. dybowskii lacks heterotypic sex chromosomes, limiting the in-depth study of sex determination and sex reversal mechanisms. Previous studies have shown that certain environmental factors can modify R. dybowskii genotypic females into phenotypic males, but the mechanism is still unknown. Considering the difficulties in identifying and collecting sex reversal gonads at different stages of differentiation under natural conditions, testes from sexually mature wild adult R. dybowskii were taken in this study, and the genotypic sex of individuals and sex reversal were identified by two male-linked genetic markers reported in our most recent findings. Transcriptome sequencing was performed on testicular tissue from males and pseudo-males, as well as female ovary tissue. The results show that the gene expression patterns of pseudo-males’ testes were similar to those of the males but highly differed from females’ ovaries. One hundred and seventeen differentially expressed genes between testes of pseudo-males and males were found, and the up-regulation of doublesex and mab-3 related transcription factor 1 (Dmrt1) in testes of pseudo-males may play a key role in R. dybowskii sex reversal.