RNA剪接及調控機制 | RNA splicing and its regulation

核心概念

Splice Site (SS)

位於外顯子與內含子的交界處，能夠被剪接體（spliceosome）識別的內含子序列。

分為5'ss (donor site)、3'ss (acceptor site)。

5'ss中的5’指的是5'-intron

3'ss中的3’指的是3'-intron

Branching Point (BP)

位於內含子3'ss上游（50nt內）的部分保守序列，在剪接過程中能與5'ss結合形成分支。

Note. From “RNA Splicing by the Spliceosome,” by M. E. Wilkinson et al., 2019, Annual review of biochemistry, 89, p. 362.

RNA Splicing

剪接步驟

1. branching
2. ligation

剪接位點

Splicing Regulation

影響剪接的序列

包括：剪接核心保守序列（core consensus sequence）、剪接調節元件（splicing regulatory elements, SREs)

• 剪接核心保守序列：5'ss、3'ss、BP
• 剪接調節元件：增強或減弱剪接體與pre-mRNA序列結合 (i.e., acting on spliceosome recruitment)
  • exonic splicing enhancer (ESE)
  • exonic splicing silencer (ESS)
  • intronic splicing enhancer (ISE)
  • intronic splicing silencer (ISS)

調控方式

cis-acting 順式作用、trans-acting 反式作用

• cis-regulation by
  • exonic splicing enhancer (ESE)
  • exonic splicing silencer (ESS)
  • intronic splicing enhancer (ISE)
  • intronic splicing silencer (ISS)
• trans-regulation by
  • SR proteins
  • hnRNPs