| Nucleic acid substances and their degradation products have a wide range of uses in the fields of genetic engineering,medicine,food,agricultural production and so on.Nucleic acids come from a wide range of sources.Among them,the content of RNA in bacteria is 0.3%-5.1%,the content of RNA in yeast is 2.7%-11%,and the content of RNA in mold is 0.7%-2.8%.It is the most common and the research hotspot in recent years.In this study,a high nucleic acid Saccharomyces cerevisiae B195 was screened by chemical mutagenesis of its parent strain BY23 in the early stage,and then genomic and transcriptome analysis of its parent strain BY23 and mutant B195 were carried out.In this project,15 differentially expressed genes related to nucleotide metabolism were screened out by analyzing the differential multiples of differential genes and the pathways involved,and then overexpression or knockout verification was performed in the parent strain BY23,thus obtaining For the corresponding mutant strains,the nucleic acid content of the mutant strains was determined by fermentation.Based on the results of transcriptomics analysis and differential gene verification,preliminary exploration of the genetic mechanism of S.cerevisiae.The main research contents and results are as follows:(1)Genomics and transcriptomics techniques were used to analyze the BY23 and B195 strains.At the genomic level,a total of 78,655 mutation sites were obtained,of which 73,202 were SNP types and 5,453 were InDel types.The coding information statistics of the mutation types of the two samples were found,and the proportions of synonymous SNV,nonframeshift deletion and nonframeshift insertion were found Over 58%;15 genes related to nucleic acid metabolism were obtained through enrichment analysis of mutant genes,but their mutation sites were all in non-coding regions.Genomics data is not ideal,and there are certain problems with genomic resequencing.At the transcription level,a total of 1989 unigenes were obtained,compared with the control group,there were 536 differentially transcribed genes.KEGG enrichment analysis showed that differentially transcribed genes were mainly enriched in yeast meiosis,ribosome production in eukaryotes,RNA transport,glyoxylic acid and dibasic acid metabolism,tryptophan metabolism,yeast MAPK signal Pathways and metabolic pathways such as multi-species lifespan mediation pathways.(2)Among the 15 construction strains,the nucleic acid content of the construction strain overexpressing the YHR094C gene encoding the glucose transporter was found to be 8.19%higher than that of the starting strain BY23;the nucleic acid content of the construction strain knocking out the YOR185C gene encoding the GTP binding protein was increased by 11.6%;Knocking out the nucleic acid content of the YOR185C gene encoding catalase increased by 14%.Over-expression of YHR094C gene and knockout of YOR185C gene can improve the energy supply in the cell and promote the growth and reproduction of the cell;knocking out of YOR185C gene may make the intracellular redox homeostasis get a higher level of balance and promote the cell RNA biosynthesis.Subsequent knockout overexpression was followed to construct the BY958 strain,which increased the nucleic acid content by 16.76%compared to the starting strain.It is inferred that there may be a coordination relationship between the YHR094C gene,YOR185C gene and YGR088W gene during the metabolism of high nucleic acid S.cerevisiae(3)The growth curve of the parent strain and the four mutant strains was drawn.It was found that the growth rate of the mutant strain was higher than that of the parent strain.The growth rate of the mutant strain was closely related to the high nucleic acid S.cerevisiae,that is,the higher the growth rate,the higher the nucleic acid content... |
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