The Role Of Pink1/Parkin In The Development Of Midgut In Drosophila Melanogaster Metamorphosis

Autophagy proceeds in a low basal level in almost all cells to perform homeostatic functions but is rapidly upregulated in some conditions,for example,during insect metamorphosis massive cells require elimination.Although autophagy is primarily known as a pro-survival mechanism to enable cell survival during cell stress(such as nutrient deprivation),recent evidences link autophagy to nonapoptosis programmed cell death during development.The dying Drosophila larval intestine undergoes drastic morphology changes during the onset of metamorphosis that requiring a large reduction in midgut length and autophagy in enterocytes,which seems to be caspase independent.Mutations in PINK1 and PARKIN cause neurodegenerative disorders--Parkinson disease.In mammalian cells,PIINK1 targets to depolarized mitochondria,and then selectively recruit PARKIN to mitochondria.PARKIN catalyzes outer membrane proteins ubiquitination and stimulates mitochondrial autophagy.Both PINK1 and PARKIN function in mitochondrial quality control.Moreover,studies have shown that loss of PINK1 impairs stress-induced autophagy in mammalian cells,decreasing the expression level of Beclin?and LC3 gene.Taken together,PINK1 participates in the clearance of mitochondria and autophagy in pathological conditions or stress induced conditions.However,some normal development processes,such as Drosophila metamorphosis,whether PINK1 and PARKIN are involved in mitochondrial clear and autophagy is not clear at present.We constructed hsFLP;pmcherry.Atg8/cyo;Actin<<Gal4,UAS nlsGFP/T6 drosophila melanogaster strain and hsFLP;Actin<<Gal4,UAS-myrRFP;sqh:mito-EYFP drosophila melanogaster strain as female parent,coupled with male drosophila melanogaster from various PINK1,or PARKIN transgenic manipulated strains respectively,and then collect the larvae of their F1 generation.After heat shock treatment we contrasted transgenic clone cells against control cells around cells them from mitochondrial quality control and autophagy.We showed that intestinal cells undergo programmed cell death——autophagy during drosophila metamorphosis.PARKIN and PINK1 regulate the clearance of mitochondria.The expression change of PARKIN and PINK1 protein or mutations may also affect the development process,such as PINK1 RNAi delay rather than inhibit cells shrink,moreover reduce cell autophagy level at the same time.So far as we know,we reported PINK1/PARKIN work in the removal of mitochondria in the process of midgut development,which revealed that not only pathological state or stress condition but some development process also requires them.