The effects of tissue-specific DHS (Deoxyhypusine synthase) levels on locomotion and longevity of a fruit fly

Krivograd, Anja (author), Glavan, Gordana (mentor), Sigrist, Stephan (co-mentor)

Deoxyhypusine synthase (DHS), named CG8005 in the fruit fly Drosophila melanogaster tissues, is an important enzyme involved in the hypusination of eukaryotic translation initiation factor 5A (eEIF5A). Hypusination is essential for eEIF5A functioning in many cellular processes, such as the translation of mitochondrial and autophagic proteins. The purpose of this study was to explore the effects of changed levels of hypusination altered by the knockdown or overexpression of the CG8005 gene in neuronal tissue, fat body, and whole body on locomotion of a fruit fly. To better understand the importance of hypusination at different stages of development in a fruit fly the effects of CG8005 neuronal knockdown induced in adulthood and throughout life on locomotion and longevity were compared. The final purpose was to find out if caloric restriction would prolong lifespan and improve locomotion in hypusination deprived flies by increasing the hypusine levels. Locomotion and longevity assays were done, and the concentration of hypusine in fly brains was determined by Western Blot. We found that locomotion was unaffected by hypusination attenuation in the neurons, the fat body, and the whole fly body. Similarly, locomotion was not improved upon upregulation of the CG8005 gene in neurons. Western Blot analysis of fly brain with life- long neuronal CG8005 knockdown did not show a difference in hypusine signal. This work failed to show that hypusination is critical for locomotion and lifespan in early development or adulthood. Caloric restriction significantly extended the life span of healthy as well as hypusination attenuated flies, and in both cases, also increased the amount of hypusine in fly brains. Thus the benefits of caloric restriction did not show to be dependent on functional hypusination. However, as this is the first study to estimate the correlation between hypusination and caloric restriction, more research is needed.

• Language: English
• Keywords: Drosophila melanogaster, hypusination, autophagy, deoxyhypusine synthase, caloric restriction, locomotion, lifespan
• Work type: Master's thesis/paper
• Organization: BF - Biotechnical Faculty
• Year: 2020
• PID: 20.500.12556/RUL-120708
• COBISS.SI-ID: 35139843
• Publication date in RUL: 25.09.2020

Secondary language

• Language: Slovenian
• Title: Vpliv tkivno specifične spremembe ravni deoksifuzin sintaze na lokomocijo in dolgoživost vinske mušice

Abstract

Deoksifuzin sintaza (DHS), imenovana CG8005 v tkivih vinske mušice Drosophila melanogaster, je pomemben encim, ki sodeluje pri hipuznaciji evkariontskega translacijskega faktorja 5A (eIF5A). Hipuzinacija je bistvena za delovanje eIF5A pri mnogih celičnih procesih, kot so prevajanje mitohondrijskih in avtofagnih proteinov. Namen te študije je bil raziskati učinke sprememb nivoja hipuzinacije na lokomocijo preko znižanja ali zvišanja nivoja izražanja CG8005 gena v nevronih, maščobnem telesu in celem telesu na lokomocijo. Za boljše razumevanje pomena hipuzinacije na različnih razvojnih stopnjah vinske mušice smo primerjali učinke znižanja nevralnega izražanja CG8005 med celim življenjem in v odraslosti na lokomocijo in življenjsko dobo. Končni namen je bil ugotoviti, ali kalorična restrikcija podaljša življenjsko dobo in izboljša lokomocijo živali z oslabljeno nevralno hipuzinacijo preko povečanja ravni hipuzina. Izvedli smo teste lokomocije in teste dolgoživosti, ter opredelili količino hipuzina v možganih živali s prenosom po Westernu. Ugotovili smo, da oslabitev hipuzinacije v nevronih, maščobnem telesu in celem telesu ni vplivala na lokomocijo. Prav tako, tudi povečanje izražanja CG8005 v nevronih ni izboljšalo lokomocije. Analiza prenosa po Westernu v možganih mušic z vseživljenjsko oslabitvijo CG8005 ni pokazala razlike v nivoju hipuzina v primerjavi s kontrolno skupino. Ta raziskava ni pokazala, da je hipuzinacija ključnega pomena za lokomocijo in življenjsko dobo v zgodnjem razvoju ali v odraslosti. Kalorična restrikcija je znatno podaljšala življenjsko dobo zdravih živali, pa tudi tistih z oslabljeno nevralno hipuzinacijo, in v obeh primerih tudi povečala količino hipuzina v možganih. Učinki kalorične restrikcije niso pokazali odvisnosti od funkcionalne hipuzinacije. Ker je to prva študija, ki proučuje povezavo med hipuzinacijo in kalorično restrikcijo, je potrebnih še več nadaljnjih raziskav.

• Keywords: Drosophila melanogaster, hipuzinacija, avtofagija, deoksifuzin sintaza, kalorična restrikcija, lokomocija, življenjska doba