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Adenovirus genomes are linear, non-segmented double-stranded (ds) DNA molecules that are typically 26-46 Kbp long, containing 23-46 protein-coding genes.〔 (【引用サイトリンク】 Viruses – Complete Genomes )〕 The example used for the following description is Human adenovirus E, a mastadenovirus with a 36 Kbp genome containing 38 protein-coding genes.〔 (【引用サイトリンク】 Human Adenovirus E Genome )〕 While the precise number and identity of genes varies among adenoviruses, the basic principles of genome organization and the functions of most of the genes described in this article are shared among all adenoviruses. == Transcription units == The 38 genes in the Human Adenovirus E genome are organized in 17 transcription units, each containing 1-8 coding sequences.〔 (【引用サイトリンク】 Human adenovirus E overview )〕 Alternative splicing during processing of the pre-mRNAs produced by each transcription unit enable multiple different mRNAs to be produced from one transcription unit. The E1A, E1B, E2A, E2B, E3, and E4 transcription units are successively transcribed early in the viral reproductive cycle. The proteins coded for by genes within these transcription units are mostly involved in regulation of viral transcription, in replication of viral DNA, and in suppression of the host response to infection.〔 (【引用サイトリンク】 Adenoviruses )〕 The L1-L5 transcription units are transcribed later in the viral reproductive cycle, and code mostly for proteins that make up components of the viral capsid or are involved in assembly of the capsid. The L1-L5 transcription units are all regulated by the same promoter region and share the same transcription start site. As a result, transcription of all five late transcription units begins at the same point in the viral reproductive cycle.〔 〕 Transcription of pre-mRNAs beginning at the late promoter is randomly terminated at one of five termination sites, producing a population of transcripts of five different lengths. The pre-mRNAs of any given length are then alternatively spliced to produce 1-4 different mRNAs coding for a corresponding number of proteins. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Adenovirus genome」の詳細全文を読む スポンサード リンク
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