Potential contributions of heat shock proteins and related genes in sexual differentiation in yellow catfish (Pelteobagrus fulvidraco)

Abstract

Sex determination and differentiation in ectotherms are very complicated affairs and usually affected by both genetic and environmental factors. Because of their temperature-sensitive expression, heat shock proteins (HSPs) are good candidates for temperature-dependent sex determination (TSD). Similar to most thermosensitive fish species, the male to female ratio increases with temperature in yellow catfish (Pelteobagrus fulvidraco). Yellow catfish is also a type of sexual size dimorphic fish, and the male individuals grow much faster than females of the same age. Therefore, research of sex differentiation in yellow catfish is important in aquiculture. In this attempt, a total of seven HSPs and related genes were identified from transcriptomes of yellow catfish by 454 pyrosequencing and Solexa sequencing that we did previously, including five genes with complete open reading frame (ORF). Phylogenetically, all these genes were compared with their counterparts from other vertebrates. All these genes were sex-biased expressed in gonads. Hspa5, Hip, and Cdc37 were expressed more highly in ovary than in testis, whereas Hsp90α, Hspb2, Hspb8, and Hspbp1 were expressed more highly in testis than in ovary. Additionally, the expression of these genes was assessed after 17α-methyltestosterone (MT) and 17α-ethinylestradiol (EE2) treatment, respectively. Our result showed that working as co-chaperones, these HSPs and related genes may regulate sex steroid receptor activities to influence gonad development in yellow catfish. Our work would help in the understanding of the mechanism of sexual differentiation in teleosts.

Gender-specific responses in gene expression of Nile tilapia (Oreochromis niloticus) to heavy metal pollution in different aquatic habitats

“…Furthermore, males showed a significant upregulation in the expression of the HSP27 gene compared to females. This rise in HSP27 expression may be caused by the physiological difference between males and females, as HSPs are expressed more highly in the testicles than in the ovaries 82 . Similarly, the expression of HSP90 and HSP70 was significantly suppressed in gilthead sea bream, Sparus aurata, samples exposed to sediments with high metal concentrations 83 .…”

Identification of BiP as a temperature sensor mediating temperature-induced germline sex reversal

“…Firstly, our study found that in addition to functioning in driving oocyte fate in C. elegans hermaphrodites, BiP is also required to promote oocyte fate in a male/female nematode species, supporting the role of BiP in modulating germline sex in both hermaphrodites and dioecious animals. Furthermore, it has been previously shown in fish (He, Fang et al, 2017), the expression of heat shock responses proteins (HSPs) are highly correlated with sex reversal (Kohno et al, 2010), also suggesting that these HSP proteins such as BiP may act as temperature sensors to mediate TGSD in these animals. Notably, studies in turtles have shown that Ca 2+ may affect STAT3 expression to mediate TSD, but the molecular mechanism that mediates the effect of temperature on Ca 2+ release to modulate sex needs further elucidation (Weber et al, 2020).…”