The spatio-temporal expression analysis of parathyroid hormone like hormone gene provides a new insight for bone growth of the antler tip tissue in sika deer

Abstract

Title of the manuscript: The spatio-temporal expression analysis of parathyroid hormone like hormone gene provide a new insight for bone growth of the antler tip tissue in sika deer ABSTRACT Objective: Parathyroid hormone like hormone (PTHLH), as an essential factor for bone growth, is involved in a variety of physiological processes. The aim of this study was to explore the role of PTHLH gene in the growth of antler. Methods: The coding sequence (CDS) of PTHLH gene cDNA was obtained by cloning in sika deer (Cervus nippon), and the bioinformatics was analyzed. The quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the differences expression of PTHLH mRNA in different tissues of the antler tip at different growth periods (early period, EP; middle period, MP; late period, LP). Results:The CDS of PTHLH gene was 534bp in length and encoded 177 amino acids.Predictive analysis results revealed that the PTHLH protein was a hydrophilic protein without transmembrane structure, with its secondary structure consisting mainly of random coil. The PTHLH protein of sika deer had the identity of 98.31%, 96.82%, 96.05% and 94.92% with Cervus canadensis, Bos mutus, Oryx dammah and Budorcas taxicolor, which were highly conserved among the artiodactyls. The qRT-PCR results showed that PTHLH mRNA had a unique spatio-temporal expression pattern in antler.In the dermis, precartilage, and cartilage tissues, the expression of PTHLH mRNA was extremely significantly higher in MP than in EP, LP (p<0.01). In the mesenchyme A c c e p t e d A r t i c l e 5 tissue, the expression of PTHLH mRNA in MP was significantly higher than that of EP (p<0.05), but extremely significantly lower than that of LP (p<0.01). The expression of PTHLH mRNA in antler tip tissues at all growth periods had approximately the same trend, that is, from distal to basal, it was first down-regulated from the dermis to the mesenchyme and then continuously up-regulated to the cartilage tissue. Conclusion:PTHLH gene may promote the rapid growth of antler mainly through its extensive regulatory effect on the antler tip tissue.