The Systematic Study On Histone Sites Or Modification Regulation Of Cell Autophagy

Autophagy is a highly conserved degradation system,which is widely present in mammalian cells,plant cells and yeast cells.Autophagy is an important mechanism for cells to maintain homeostasis,and there is a complex and close relationship with other biological processes.The activity of autophagy is regulated at different levels including signal transduction pathways,post-translational modification regulation and transcription regulation.There are few studies on the regulation of autophagy at transcriptional level.Recently studies have found that some modifications modulate affect autophagy by regulating the expression of autophagy-related genes.Histone modifications get more and more attention in autophagy regulation.However,there is no systematic study on the regulation of autophagy by histone H3 and H4 modifications.In this study,we took Saccharomyces cerevisiae as the experimental object,and first constructed a 205 amino acid point mutant library of H3 and H4 containing the reporter gene GFP Atg8.The reporter gene GFP Atg8 is an indicator of autophagy.The value of Free GFP/GFP-Atg8 is detected by Western blots to represent the degree of autophagy.Under normal conditions and nitrogen starvation conditions,through the first round of screening,we explored the effects of different histone residue mutations on autophagy in yeast cells;then we performed the second round of screening to confirm the stable changes in the first round of screening.In addition,we also focused on the presence of covalently modified histone residue sites,and studied the relationship between different types of histone modifications and autophagy.The results of the study showed that among histone H3/H4 point mutation sites,there are nine histone sites that inhibit autophagy,namely H3R2,H3T3,H3T6,H3V46,H3R49,H3E50,H3S57,H4R36,H4S64;five histone sites that promote autophagy are H3K36,H3K79,H4I29,H4I46,H4H75.Among the point mutation sites with histone methylation modification,the sites that inhibit autophagy are H3R2,H3K4,and H3R8;the sites that promote autophagy are H3K36 and H3K79.Among the point mutation sites with histone acetylation modification,the sites that inhibit autophagy include H3K9,H3K14,H3K18,H3K23,H3K56,H4K5,and H4K91;sites that promote autophagy include H4K16 and H4K44.Among the mutation sites with histone phosphorylation modification,the sites that inhibit autophagy are H3T3,H3T6,and H3T11;the site that promote autophagy is H4S1.In summary,our research provides a panoramic understanding on the regulation of cell autophagy by histone modifications.Our study also provides an important clue and direction for subsequent study on the biological role of histone modifications.