請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/21424
標題: Genomic Sequence and Analysis of Corynephage P1201
噬菌體 P1201 基因組之解碼及分析
作者: 陳昶霖
Chen, Chang-Lin
關鍵字: phage
噬菌體
Corynebacterium glutamicum
味精生產菌
出版社: 分子生物學研究所
摘要: P1201 is a lytic corynephage of Corynebacterium glutamicum NCHU 87078. The linear double—stranded DNA genome was 70,579 bp, with 3'—protruding cohesive ends of ten nucleotides and an overall G+C content of 50.9%. Analysis of complete genome with cumulative GC skew diagrams, the low point, near the left end, with short repeats and lacking ORFs, might be the site of replication origin. One hundred and fifteen open reading frames were identified. The genomic organization of the putative coding regions was very similar to that of mycobacteriophage. Four tRNA—like sequences (two tRNA—Arg, one tRNA—Trp, and one tRNA—Gly) were found, in which two tRNA—Arg genes for codons AGA and AGG are rare in C. glutamicum. The genes required for rgulation, packaging, head assembly, tail assembly, lysis, replication in P1201 genome were homologous to mycobacteriophage Omega, mycobacteriophage Che8, actinophage VWB, mycobacteriophage CJW1, mycobacteriophage Bxz2, mycobacteriophage Barnyard and bacteriophage SPβ respectively. Corynephage P1201 had three inteins which integrate into ORF 27 (thymidylate synthase), ORF 34 (terminase), and ORF 87 (RNR α subunit), respectively. To our knowledge, this is the first report that intein has been integrated into thymidylate synthase gene. The existence of three inteins in corynephage genome may play important roles in the horizontal exchange of genetic material during evolution. The mosaic—like genome of P1201 indicated the occurrence of horizontal gene exchange among corynephages, mycobacteriophages, Corynebacteriaceae, and Mycobacteriaceae in corynephage P1201 evolution. We suggested that corynephages and mycobacteriophages come from the same pool.
Corynephage P1201 是從味精生產菌 Corynebacterium glutamicum NCHU 87078 分離出來的溶裂性噬菌體。基因組由 70,579 bp 雙股 DNA 所組成,染色體 3’ 末端凸出是由 10 個核苷酸所組成。整個基因組的 G+C 含量為 50.9%。利用 GC skew 分析其差值最低點位於左邊端點,此區域可能是複製的啟始區;最高點在 39 kb 左右的位置,可能是複製的終止區。利用生物資訊分析其基因組後,推測噬菌體 P1201 含有 115 個基因,包括 111 個開放讀碼區和 4 個 tRNA 基因 (兩個 tRNA—Arg,一個 tRNA—Trp 和一個 tRNA—Gly)。這兩個 tRNA—Arg 所對應的密碼為 AGA 和 AGG,目前已知帶有這兩組反密碼的 tRNA 在 C. glutamicum 中是較稀少的。噬菌體 P1201 基因組之功能由 5’ 端到 3’ 依序為:Regulation—Packaging—Head assembly—Tail assembly—Lysis—Replication—Regulation,這些區域的蛋白質分別和 mycobacteriophage Omega、mycobacteriophage Che8、actinophage VWB、mycobacteriophage Cjw1、mycobacteriophage Bxz2、mycobacteriophage Barnyard 及 bacteriophage SPβ 有很高的相似度。噬菌體 P1201 含有三個 intein,分別插在 ORF 27 (thymidylate synthase)、ORF 34 (terminase) 及 ORF 87 (RNR α subunit) 之中。據我們所知,這是第一個發現有 intein 插入 thymidylate synthase 基因的例子。在基因組演化過程中,此三個 intein 可能會導致基因的水平轉移,而造成基因重組的變異。噬菌體 P1201 基因組呈現出高度馬賽克的結構,顯示此噬菌體在演化過程中,和 corynephages 與 mycobacteriophages 噬菌體及 Corynebacteriaceae 與 Mycobacteriaceae 菌體之間存在基因水平轉移的現象,另一方面藉由分析噬菌體 P1201 的基因組可推測 corynephages 和 mycobacteriophages 是來自相同的生物庫。
URI: http://hdl.handle.net/11455/21424
顯示於類別:分子生物學研究所

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