In Genome And Transcriptome-wide Analysis Of Insect Autophagy-related Genes And Their Response To Acmnpv Infection

In eukaryotic cells,autophagy plays a critical role in delivering macromolecules and organelles from the cytoplasm to lysosomes for degradation.Autophagy is essential for maintaining the homeostasis of host cells and also critical for defense the infection of pathogens.The atuophagy pathway is envolutionarily conserved in yeast,insects and mammalian cells.Recently,more than 30 autophagy-related genes(ATG)has been identified in Saccharomyces cerevisiae,and most of these genes are also characterized in mammals.Based on the diversity of function of ATG proteins,they have been grouped into 6 distinct functional complexes,which include the ATG1 kinase complex,the class III phosphatidylinositol 3-kinase(PI3K)complex,the ATG8 and ATG12 conjugation systems,the PI(3)P-binding ATG2-ATG18 complex,and ATG9.Presently,little is known about the orthologs of ATG proteins in sequenced insect genomes and their evolutionary relationships with those from yeast and mammals.Also,largely is unknown about the roles of ATG proteins in baculoviruses infection.In this study,we carried out genomic comparative analysis of ATG proteins in yeast,humans,and 14 sequenced insect genomes representing the species form Orders Hymenoptera,Diptera,Hemiptera,Phthiraptera,Lepidoptera,and Coleoptera.Based on amino acid sequence alignments,domain/motif structure analysis,and phylogenic analysis,we found that most of the components of the autophagy pathway are evolutionarily conserved across yeast,insects,and humans.Compared with the large gene expansion in humans of ATG genes,we only found 4 ATG genes(ATG4,ATG8,ATG18,and Snf1p)were expanded in insect genomes.Further analysis of the transcriptome database,which is derived from AcMNPV-infected Trichoplusia ni Tnms42 cell lines,we retrieved the expression data for 35 ATG genes.Compared with the non-infected control cells,we found that,in the early stage of infection(0-6 hours),the expression of cellular ATG genes were showed in two distinct patterns.The expression of one group ATG genes were dramatically up-regulated,which includes but not limited as AKT,ATG12,ATG24,ATG37,BRE5,FUNDC1,P62,SCH9 P,TSC13,whereas the expression of other group ATG genes were significantly down-regulated,which includes but not limited as ATG2,ATG13,ATG17,ATG35,ATG101,BNIP3,WIPI1/2,PRKIN.Considering the entry of AcMNPV to nucleus for start infection,we proposed that there is a complex interplay between AcMNPV infection and host celluar autophagy pathway.The primary data based on the comparative genomic and transcriptome analysis will be useful for further identifying the roles of the autophagy pathway in baculoviruses infection.