-
PloS One 2020Fish oogenesis is characterised by a massive growth of oocytes each reproductive season. This growth requires the stockpiling of certain molecules, such as ribosomal...
Fish oogenesis is characterised by a massive growth of oocytes each reproductive season. This growth requires the stockpiling of certain molecules, such as ribosomal RNAs to assist the rapid ribosomal assembly and protein synthesis required to allow developmental processes in the newly formed embryo. Massive 5S rRNA expression in oocytes, facilitated by transcription factor 3A (Gtf3a), serves as marker of intersex condition in fish exposed to xenoestrogens. Our present work on Gtf3a gene evolution has been analysed in silico in teleost genomes and functionally in the case of the zebrafish Danio rerio. Synteny-analysis of fish genomes has allowed the identification of two gtf3a paralog genes, probably emerged from the teleost specific genome duplication event. Functional analyses demonstrated that gtf3ab has evolved as a gene specially transcribed in oocytes as observed in Danio rerio, and also in Oreochromis niloticus. Instead, gtf3aa was observed to be ubiquitously expressed. In addition, in zebrafish embryos gtf3aa transcription began with the activation of the zygotic genome (~8 hpf), while gtf3ab transcription began only at the onset of oogenesis. Under exposure to 100 ng/L 17β-estradiol, fully feminised 61 dpf zebrafish showed transcription of ovarian gtf3ab, while masculinised (100 ng/L 17α-methyltestosterone treated) zebrafish only transcribed gtf3aa. Sex related transcription of gtf3ab coincided with that of cyp19a1a being opposite to that of amh and dmrt1. Such sex dimorphic pattern of gtf3ab transcription was not observed earlier in larvae that had not yet shown any signs of gonad formation after 26 days of oestradiol exposure. Thus, gtf3ab transcription is a consequence of oocyte differentiation and not a direct result of estrogen exposure, and could constitute a useful marker of gonad feminisation and intersex condition.
Topics: Animals; Cichlids; Disorders of Sex Development; Evolution, Molecular; Female; Fish Proteins; Gene Duplication; Male; Oogenesis; Ovary; Phylogeny; Sex Characteristics; Sex Differentiation; Synteny; Transcription Factor TFIIIA; Zebrafish; Zebrafish Proteins
PubMed: 31999691
DOI: 10.1371/journal.pone.0227690 -
BMC Genomics Jan 2020Spermatogenesis is an intricate process regulated by a finely organized network. The orange-spotted grouper (Epinephelus coioides) is a protogynous hermaphroditic fish,...
Transcriptome profiling of laser-captured germ cells and functional characterization of zbtb40 during 17alpha-methyltestosterone-induced spermatogenesis in orange-spotted grouper (Epinephelus coioides).
BACKGROUND
Spermatogenesis is an intricate process regulated by a finely organized network. The orange-spotted grouper (Epinephelus coioides) is a protogynous hermaphroditic fish, but the regulatory mechanism of its spermatogenesis is not well-understood. In the present study, transcriptome sequencing of the male germ cells isolated from orange-spotted grouper was performed to explore the molecular mechanism underlying spermatogenesis.
RESULTS
In this study, the orange-spotted grouper was induced to change sex from female to male by 17alpha-methyltestosterone (MT) implantation. During the spermatogenesis, male germ cells (spermatogonia, spermatocytes, spermatids, and spermatozoa) were isolated by laser capture microdissection. Transcriptomic analysis for the isolated cells was performed. A total of 244,984,338 clean reads were generated from four cDNA libraries. Real-time PCR results of 13 genes related to sex differentiation and hormone metabolism indicated that transcriptome data are reliable. RNA-seq data showed that the female-related genes and genes involved in hormone metabolism were highly expressed in spermatogonia and spermatozoa, suggesting that these genes participate in the spermatogenesis. Interestingly, the expression of zbtb family genes showed significantly changes in the RNA-seq data, and their expression patterns were further examined during spermatogenesis. The analysis of cellular localization of Eczbtb40 and the co-localization of Eczbtb40 and Eccyp17a1 in different gonadal stages suggested that Eczbtb40 might interact with Eccyp17a1 during spermatogenesis.
CONCLUSIONS
Our study, for the first time, investigated the transcriptome of the male germ cells from orange-spotted grouper, and identified functional genes, GO terms, and KEGG pathways involved in spermatogenesis. Furthermore, Eczbtb40 was first characterized and its role during spermatogenesis was predicted. These data will contribute to future studies on the molecular mechanism of spermatogenesis in teleosts.
Topics: Animals; Fishes; Gene Expression Profiling; Germ Cells; Methyltestosterone; Spermatogenesis; Transcriptome
PubMed: 31973692
DOI: 10.1186/s12864-020-6477-4 -
Brazilian Journal of Biology = Revista... 2021Synthetic androgens (male hormones) administered to fish nursery are being used in aquaculture to avoid sexual differentiation and unwanted spawning at the eggs or the...
Synthetic androgens (male hormones) administered to fish nursery are being used in aquaculture to avoid sexual differentiation and unwanted spawning at the eggs or the first feeding fry stage of fish. Present trial was conducted with the aim to produce male common carp (Cyprinus carpio) by egg immersion technique. Through this little insight, the effect of different hormone concentrations (17α-methyltestosterone @ HC:150, 300, 450 and 600 µgl-1) with immersion times (IT: 24, 48 and 72 hrs) and their interaction effect (HC x IT) on the hatching percentage of Cyprinus carpio eggs, percent survival and percent of male's production was evaluated specifically. Results showed that egg hatching percentage decreased with increased IT likewise, survival of treated fry was affected by increasing the IT (P<0.001). The main interaction effect of HC x IT showed that the highest percent of male individuals (95%) was obtained at 450-600 µgl-1 HC for 72 hrs IT, followed by 88-92.50% at 150-300 µgl-1 HC for 72-hrsof IT, 87.50% at 48-hrs of IT for rest of the hormone treatments, and lowest 47.50% was recorded in control (P<0.05). Increased percent male of Cyprinus carpio was obtained with increasing HC across all ITs. It was observed that the immersion treatment at 600µgl-1 for 72 hours was more effective to change the sex ratio of pre hatch Cyprinus carpio. A comparative outlook made from this experimental trial that sex induction of Cyprinus carpio by eggs immersion using synthetic male steroid hormone is an alternative safe technique of fish sex reversal in contrast to oral administration of hormone in fish feed.
Topics: Androgens; Animals; Aquaculture; Carps; Immersion; Male
PubMed: 32901653
DOI: 10.1590/1519-6984.224681 -
Animal Reproduction 2023The females of yellowtail tetra (), known as the freshwater sardine, are approximately 1.33 times larger than males, and thus, all-female monosex culture would increase...
The females of yellowtail tetra (), known as the freshwater sardine, are approximately 1.33 times larger than males, and thus, all-female monosex culture would increase production and reduce size variability. The present work aimed to identify the optimal dose of 17α-methyltestosterone (MT) to be used in the masculinization of for indirect sex reversal. Three different concentrations of MT (20, 40, and 60 mg/kg of feed in the diet) were fed to the fry for 30 days. Thirty adult individuals from each treatment, including the control (0 mg MT/kg), were evaluated for gonadal development, morphological and histological sexual identification, zootechnical performance, and the possible genotoxic effect caused by prolonged exposure to MT. MT significantly (<0.01) affected the differentiation of the gonads, with the presence of possible inhibitory effects in all treatments. Intersex individuals were present in the 20 and 60 mg MT/kg treatments. All treatments were able to masculinize and the treatment with the lowest hormone concentration produced the highest percentage of males 76.7%, while the control had 46.7% males. The presence of erythrocyte nuclear alterations indicated a possible cytotoxic effect of MT in treatments 40 and 60 mg MT/kg, however, the use of the hormone did not affect the growth and the survival of the individuals. Thus, the use of MT is a viable option for obtaining neomales as a first step into the production of all-female progenies.
PubMed: 36922988
DOI: 10.1590/1984-3143-AR2022-0080 -
Animals : An Open Access Journal From... Aug 2023In the original publication [...].
Correction: Cai et al. Sex Reversal Induced by Dietary Supplementation with 17α-Methyltestosterone during the Critical Period of Sex Differentiation in Oriental River Prawn (). 2023, , 1369.
In the original publication [...].
PubMed: 37570355
DOI: 10.3390/ani13152489