Background: Heat shock protein 60 (Hsp60) play important roles in protecting testicular development and production of sperms. This study was conducted to investigate Hsp60 gene expression and localization in testicular development to ascertain its influence on infertility and in different tissues of the male cattle-yak and yak. A total of 54 cattle (24 cattle-yak and 30 yak) were examined. Materials and methods: Hsp60 mRNA of cattle-yak was cloned first and amino acid variations were found leading to differences at protein spatial structure compare with the yak. Real-time quantitative PCR (RT-qPCR) analysis revealed that Hsp60 mRNAs expression were different in cattle-yak and yak. Results: The results showed disparity in Hsp60 expression among different tissues and in different developmental stages of the testis. High Hsp60 expression was observed in juvenile and adult testicles. Moreover, Hsp60 expression in cattle-yak was significantly higher than yak (p < 0.01). The location of Hsp60 in tissue and testis was detected by immunohistochemistry (IHC) and immunofluorescence (IF). The results demonstrated that Hsp60 proteins located in epithelial cells, spermatocytes, sperm cells and mesenchymal cells. Conclusions: The Hsp60 proteins are expressed in different tissues, and the highest expression level was observed in the testis of the cattle-yak, which suggests that infertility of cattle-yak have some correlation with up-regulation of Hsp60. Background: Heat shock protein 60 (Hsp60) play important roles in protecting testicular development and production of sperms. This study was conducted to investigate Hsp60 gene expression and localization in testicular development to ascertain its influence on infertility and in different tissues of the male cattle-yak and yak. A total of 54 cattle (24 cattle-yak and 30 yak) were examined. Materials and methods: Hsp60 mRNA of cattle-yak was cloned first and amino acid variations were found leading to differences at protein spatial structure compare with the yak. Real-time quantitative PCR (RT-qPCR) analysis revealed that Hsp60 mRNAs expression were different in cattle-yak and yak. Results: The results showed disparity in Hsp60 expression among different tissues and in different developmental stages of the testis. High Hsp60 expression was observed in juvenile and adult testicles. Moreover, Hsp60 expression in cattle-yak was significantly higher than yak (p < 0.01). The location of Hsp60 in tissue and testis was detected by immunohistochemistry (IHC) and immunofluorescence (IF). The results demonstrated that Hsp60 proteins located in epithelial cells, spermatocytes, sperm cells and mesenchymal cells. Conclusions: The Hsp60 proteins are expressed in different tissues, and the highest expression level was observed in the testis of the cattle-yak, which suggests that infertility of cattle-yak have some correlation with up-regulation of Hsp60.

Hsp70 and Hsp90 play an important role in testis development and spermatogenesis regulation, but the exact connection between Hsp70 and Hsp90 and metabolic stress in cattle is unclear. Here, we focused on the male cattle–yak and yak, investigated the expression and localization of Hsp70 and Hsp90 in their tissues, and explored the influence of these factors on development and metabolism. In our study, a total of 54 cattle (24 cattle–yaks and 30 yaks; aged 1 day to 10 years) were examined. The Hsp90 mRNA of the cattle–yak was first cloned and compared with that of the yak, and variation in the amino acid sequence was found, which led to differences in protein spatial structure. Using real-time quantitative PCR (RT-qPCR) and Western blot (WB) techniques, we investigated whether the expression of Hsp70 and Hsp90 mRNA and protein are different in the cattle–yak and yak. We found a disparity in Hsp70 and Hsp90 mRNA and protein expression in different non-reproductive organs and in testicular tissues at different stages of development, while high expression was observed in the testes of both juveniles and adults. Moreover, it was intriguing to observe that Hsp70 expression was significantly high in the yak, whereas Hsp90 was high in the cattle–yak (p < 0.01). We also examined the location of Hsp70 and Hsp90 in the testis by immunohistochemical (IHC) and immunofluorescence (IF) techniques, and the results showed that Hsp70 and Hsp90 were positive in the epithelial cells, spermatogenic cells, and mesenchymal cells. In summary, our study proved that Hsp70 and Hsp90 expressions were different in different tissues (kidney, heart, cerebellum, liver, lung, spleen, and testis), and Hsp90 expression was high in the testis of the cattle–yak, suggesting that dysplasia of the cattle–yak may correlate with an over-metabolism of Hsp90.

The aim of this study is to investigate the expression and localization of HSP70/90 in different tissues and explore the regulation effects of HSP70/90 at lactation period of female yaks. HSP90 mRNA was cloned from the heart samples of female yaks, Quantitative real-time (qRT-PCR), Western blotting (WB), immunohistochemistry and immunofluorescence assays were utilized to analyze the expressions of HSP70/90 mRNA and protein in different tissues. Sequence analysis showed that HSP90 is a conserved molecular chaperone of female yaks. The qRT-PCR, WB results showed that the expressions of HSP70/90 mRNA and protein were significantly different in different tissues, and 3-fold higher expression during the lactation period than the non-lactation period of breast tissue (P < 0.01). Immunohistochemistry and immunofluorescence assays results showed that HSP70/90 were located in the cardiac muscle cells, cerebellar medulla, theca cells lining at the reproductive system, and the mammary epithelia of the breasts. In addition, the expression level of HSP70 was higher than those of HSP90 in all examined tissues. Therefore, our results strongly suggest that the expression and localization of HSP70/90 could provide significant evidence to further research in tissue specific expression, and lactation function of female yaks.