自我剪接

The basic reaction for this kind of splicing is different from the normal splicing: there is no attacking adenosine nucleotide, and no lariat is formed. Instead, the 5’ splice site is broken by attack from a G outside of the transcript. Then, the free end of the exon attacks the 3’ splice site, displacing the intron and forming a new bond with the next exon. Introns that are spliced this way are called a group I introns.

這種剪接的基本反應與正常的剪接反應不同：它沒有進攻性的腺嘌呤核苷酸，也不形成套索結構。相反，內含子在5’剪接位點受到的威脅來自於轉錄產物之外的鳥嘌呤核苷酸。之後外顯子的自由末端發起對3’剪接位點的攻擊，替代了內含子而與後面的外顯子形成新的鍵。以這樣的方式進行剪接的內含子稱為I類內含子。