Анализ транскрипционной активности подсемейств AluYa5 и AluYb8 в геноме человека при старении и долголетии

According to one of the modern concepts of human aging and longevity, the cause of the degradation of endogenous processes is the increased genome instability with age. Factors of genetic instability include transposons, or mobile genetic elements. Alu-retrotransposons are ubiquitous in the human genome. Among the members of this family, AluYa5 and AluYb8 are the only ones that retained transpositional activity. To test the hypothesis about the role of of AluYa5 and AluYb8 transposons activity in human aging and longevity, we performed the comparative analysis of their expression level among individuals of different ages. The study group included 75 healthy residents of the Republic of Bashkortostan aged between 21 and 97 years. The total sample was divided into the following groups according to age: middle-aged (38 people, 21-39 years old), elderly (23 people, 82-89 years old) and a group of long-livers (14 people, 90-97 years old). RNA samples were isolated from leukocytes of peripheral venous blood by the standard method using Trizol reagent. Quantitative analysis of AluYa5-RNA and AluYb8-RNA in blood leukocytes was performed by real-time PCR. The relative amount of mRNA was determined using the ΔΔCt method. Comparison of age groups was carried out using one-way analysis of variance with the Kruskal-Wallis test. In the total analyzed sample, the expression levels of AluYa5 and AluYb8 were 0.84 and 0.80 rel. units respectively. According to the results of comparative analysis of AluYa5-RNA and AluYb8-RNA in blood leukocytes of people from three age groups, there were no statistically significant differences in the expression of AluYa5 (H = 3.59, p = 0.17) and AluYb8 (H = 2.65, p = 0.27). After combining the groups of elderly people and long-livers and comparing them with middle-aged people, the differences in the median values also did not reach the level of statistical significance (p = 0.1). At the same time, people aged 82 and older demonstrated lower level of expression of AluYa5 subfamily (0.75 versus 2.69 rel. units) and AluYb8 subfamily (0.73 versus 2.15 rel. units). There were no statistically significant changes in the relative expression level of the AluYa5 and AluYb8 subfamilies with age in the study group.