Gene Expression Profiles Of Chlamydophlia Psittaci During The Normal Developmental Cycle And Persistence

[Objective]Using c DNA microarray techniques to detect and analyse differentially expressed genes of the C. psittaci 6BC genome between normal developmental cycle and interferon-γ induced persistence, to screen important candidate genes related to the persistence, and to investigate the possible molecular mechanism of C. psittaci persistent infections. [Methods]To induce acute infection: He La cells were infected with C. psittaci 6BC, taken out from the incubator after 2 h, abandoned the infection liquid, replaced with DMEM + 10% FBS, cultured the cells in 37 ℃.1.To induce persistent infection: He La cells were infected with C. psittaci 6BC, added recombinant human IFN-γ（rh IFN-γ） at the medium 35 ng/m L additionally, taken out from the incubator after 2 h, abandoned the infection liquid, replaced with DMEM+10% FBS+35ng/m L rh IFN-γ.2.Collecting cells of acute group and persistence group respectively at 6, 12, 24, 36, 48, 60 h later. Isolated the Cps RNA, genes of this two groups were detected by 8×15K Agilent C. psittaci whole genome microarray to screen the differentially expressed genes, with Absolute Fold change ≥2 as obvious up-regulated genes and Fold change ≤0.5 as obvious down-regulated genes, and conform part of the differential genes by Realtime-PCR.[Results]There are 287 persistent differentially expressed genes during 12⁶0h, including 74 up-regulated genes and 213 down-regulated genes, which are involved in a variety of molecular function. Gene Ontology classfication analysis had shown, there were 21 up-regulated genes participated in 1 BP categories which about translation, ESAE score was 3.58 E-09.58 down-regulated genes participated in 8 GO BP categories, in which “oxidation reduction”, “tetrapyrrole biosynthetic process”, “tetrapyrrole metabolic process” had the lowest EASE Score.There were 57 up-regulated genes participated in 4 GO MF categories, in which“structural molecule activity”, “structure constituent of ribosome” and“ r RNA binding” had the lowest ESAE Score, all ﹤9.6E-6. There were 41 down-regulated genes participated in 8 GO MF categories, in which “nucleotidyl transferase activity”, “sodium ion binding”, “oxidoreductase activity” had the lowest EASE Score.The pathway analysis had shown, through the database of “KEGG Pathway”, when EASE Score <0.1, there were 18 up-regulated genes participated in 1 “KEGG Pathway”. 38 down-regulated genes participated in 5 “KEGG Pathway”.The result of DAVID “Functional Annotation Clustering” analysis had shown, the up-regulated genes involed in 4 cluster, the cluster which had highest Enrichment Score were associated with the synthesis of r RNA. The down-regulated genes involved in 23 cluster, the cluster which had highest Enrichment Score were associated with some biosynthesis and metabolism.Using Realtime-PCR to identity the expression of these genes: CPSIT₀739（6h）, CPSIT₀043（12h）, CPSIT₀531（36h）, CPSIT₀555（48h）. All the results were same as the microarray results. [Conclusion]1.We have contruct differential gene expression profiles of C. psittaci genome between persistent infection and acute infection. 2.We have screened 287 differentially expressed genes during 12⁶0h of acute and persistence infection, including 74 up-regulated genes and 213 down-regulated genes, combined with other persistent infection model in vitro, these genes may become “persistence marker”.