Залежність тривалості життя DROSOPHILA MELANOGASTER від надекспресії та функціонального нокауту гена dNOS у нейронах

Abstract

У результаті проведених досліджень побудовано криві виживання особин з додатковою копією гена dNos та його функціональним нокаутом. Найнижчі показники середньої і максимальної тривалості життя виявлено в особин з функціональним нокаутом гена dNos, що підтверджує важливу роль NO у процесах життєдіяльності і старіння дрозофіли. Зафіксовано достовірне зниження тривалості життя також в особин з надекспресією гена dNos.

В результате проведенных исследований построены кривые выживания особей с дополнительной копией гена dNos и его функциональным нокаутом. Самые низкие показатели средней и максимальной продолжительности жизни выявлены у особей с функциональным нокаутом гена dNos, что подтверждает важную роль NO в процессах жизнедеятельности и старения дрозофилы. Зафиксировано достоверное снижение продолжительности жизни также у особей с надэкспрессией гена dNos.

In this work we used transgenic lines UAS-dNos (characterized by the presence of an additional copy of the dNos gene) and UAS-RNAi-dNos (expressed interfering RNA to dNos transcript) derived from the Bloomington Drosophila Stock Center. Individuals of these lines were crossed with individuals of the elav-Gal4 line. Accordingly, the activation of constructs took place in the first progeny precisely in neuronal cells. The wild-type Oregon line was used as control in crosses. Also, the lifespan of individuals of transgenic lines without activating constructs was checked (♀ UAS-dNos x ♂ UAS-dNos; ♀ UAS-RNAi-dNos x ♂ UAS-RNAi-dNos; ♀ elav-GAL4 x ♂ eliv-GAL4). According to the lifespan of flies from the first generation, survival curves were constructed and the rates of average and maximum lifespan were determined. Progeny with overexpression of the dNos gene (♀ elav-GAL4 x ♂ UAS-dNos) or its functional knockout (♀ elav-GAL4 x ♂ UAS-RNAi-dNos) died from the 5th day of imago's life and were characterized by significantly lower rates of average and maximum lifespan. The highest rates of lifespan were determined for the Oregon control line. In flies with functional knockout of the dNos gene the average and maximum lifespan were reduced by 50%. The decreased lifespan of progeny with functional knockout of the dNos gene confirms the important role of NO in drosophila physiology and aging. A significant decrease in lifespan was also recorded in individuals with additional copy of the dNos gene. The negative effect of NO can be mediated by its participation in the processes of excitotoxicity and nitrosylation of proteins. Excitotoxicity is associated with excessive stimulation of the ion channels and an increase of intracellular calcium concentration, which leads to further death of cells. Nitrosylation of proteins is observed in the neurons of patients with Parkinson's disease and it is thought to have a deleterious effect on brain cells. Another negative action of NO in the Drosophila is the development of neurodegeneration through the activation of the dFoxo gene, the product of which is an important transcription factor. Each of these mechanisms can be the reason of reduced lifespan of flies with dNos overexpression, but to determine the real causes additional research is necessary.