Comparative Analysis of PRNP Gene Indel Polymorphism and Expression among Zhongdian Yellow Cattle, Zhongdian Yak, and Their Hybrids.

Simple Summary: Bovine spongiform encephalopathy (BSE), a neurological disorder with a significant effect on cattle health, has been recognized pathologically and medically. It is associated with a 12 bp indel in intron 1 of the PRNP gene and a 23 bp indel polymorphism in the putative promoter. The main focus of this work was to assess the allele, genotype, and haplotype frequencies of PRNP indel polymorphisms in Zhongdian Yak, Zhongdian Yellow cattle, and Zhongdian Yakow, as well as to investigate the effect of PRNP gene expressions of 23 bp and 12 bp indels using PCR. Two variable sites—a 23 bp indel polymorphism holding AP1 binding site and a 12 bp indel polymorphism holding SP1 binding site—were also investigated. Overall, the study results suggest that the PRNP genotype may contribute to the high variation in PRNP expression. Bovine spongiform encephalopathy (BSE) is a fatal disease in cattle caused by misfolded prion proteins and linked to indel polymorphisms in the promoter and intron 1 of the PRNP gene. The aim of this study was to determine the allele, genotype, and haplotype frequencies of PRNP indel polymorphisms and to investigate the effect of PRNP gene expressions of 23 bp and 12 bp indels via polymerase chain reaction (PCR) in Zhongdian Yak (Bos-grunniens) (YK), Zhongdian Yellow cattle (Bos-taurus) (YC), and Zhongdian Yakow (Bos-primigenius taurus × Bos-grunniens) (PK). Resultant high allelic frequencies were found in 23− and 12+, while haplotype frequencies were very low in 23+/12 in YK, YC, and PK. PRNP expression was higher in the +−/−− diplotype of the PK and (mean ± SE) was 3.6578 ± 1.85964. Furthermore, two variable sites were investigated—a 23 bp indel polymorphism holding AP1 binding site and a 12 bp indel polymorphism holding SP1 binding site. Additionally, reporter gene assays revealed a link between two proposed transcription factors and lower expression levels of the +/+ allele compared with the −/− allele. The expression level of PRNP was shown to be dependent on two indel polymorphisms in the bovine PRNP promoter, which includes binding sites for RP58 and SP1 transcription factors. These findings raised the possibility that the PRNP genotype may contribute to the high variation in PRNP expression. [ABSTRACT FROM AUTHOR]