Abstract
BackgroundApoptosis plays an important role in the regulation of healthy tissue growth and development as well as in controlling the maintenance of homeostasis in exercising muscles. During an intensive physical effort, the regulation of cell death by apoptosis results in the replacement of unaccustomed muscle cells by new cells that are better suited to exercise. The aim of this study was to determine the expression of two genes (SH3FR1 and SH3RF2) that control apoptosis in muscle tissues during training periods characterized by different intensities. The gene expression levels were estimated using real-time PCR method in skeletal muscle biopsies collected from 15 Arabian horses (untrained, after an intense gallop phase, and at the end of the racing season). An association study was performed on 250 Arabian horses to assess the effect of the SH3RF2:c.796 T > C (p.Ser266Pro) variant on race performance traits in flat gallop-racing.ResultsA gene expression analysis confirmed a significant decrease (p < 0.01) in the anti-apoptotic SH3RF2 (POSHER) gene during training periods that differed in intensity. The highest SH3RF2 expression level was detected in the muscles of untrained horses, whereas the lowest expression was identified at the end of the racing season in horses that were fully adapted to the exercise. A non-significant decrease in SH3RF1 gene expression following the training periods was observed. Moreover, a serine substitution by proline at amino acid position 266 (CC genotype) was negatively associated with the probability of winning races, the number of races in which a horse occurred and the financial value of the prizes. Horses with the TT genotype achieved the highest financial benefits, both for total winnings and for winnings per race in which the horses participated.ConclusionsThe present study showed the supposed regulation mechanism of exercise-induced apoptosis in horses at the molecular level. The identified SH3RF2: c.796 T > C missense variant was associated with selected racing performance traits, which is important information during the evaluation of horses’ exercise predisposition. The association results and frequencies of the CT and TT genotypes suggest the possibility of using SH3RF2 variant in selection to improve the racing performance of Arabian horses.
Highlights
Apoptosis plays an important role in the regulation of healthy tissue growth and development as well as in controlling the maintenance of homeostasis in exercising muscles
In Arabian horses, a whole transcriptome analysis of muscle tissues showed a significant down-regulation of several genes during training periods of different intensities, but the expression of only one gene, SH3 domain containing ring finger 2 (SH3RF2 previously known as POSHER), was lower throughout all training points in untrained animals compared to fully exercise-adapted horses [10]
The authors confirmed the occurrence of the apoptotic process in gluteus medius muscles and found that it was related to the programmed death of cells unadapted to exercise conditions and their replacement by new cells that are more suited to the increased physical effort
Summary
Apoptosis plays an important role in the regulation of healthy tissue growth and development as well as in controlling the maintenance of homeostasis in exercising muscles. The aim of this study was to determine the expression of two genes (SH3FR1 and SH3RF2) that control apoptosis in muscle tissues during training periods characterized by different intensities. In Arabian horses, a whole transcriptome analysis of muscle tissues showed a significant down-regulation of several genes during training periods of different intensities, but the expression of only one gene, SH3 domain containing ring finger 2 (SH3RF2 previously known as POSHER), was lower throughout all training points in untrained animals compared to fully exercise-adapted horses [10]. The comparison of muscle transcriptomes between horses in different training periods enabled the identification of differentially expressed genes that are likely related to an adaptation to exercise intensity [10]. The stage of the research should be the verification of the selected gene’s association with the performance features via the identification of variants with a potential effect on gene expression as well as on protein activity and function
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