Fast and furious: insights of back splicing regulation during nascent RNA synthesis

Sci China Life Sci. 2021 Jul;64(7):1050-1061. doi: 10.1007/s11427-020-1881-1. Epub 2021 Feb 9.


Alternative splicing of eukaryotic precursor (messenger) RNAs in the nucleus not only increases transcriptomic complexity, but also expands proteomic and functional diversity. In addition to basic types of alternative splicing, recent transcriptome-wide analyses have also suggested other new types of non-canonical splicing, such as back splicing and recursive splicing, and their widespread expression across species Increasing lines of evidence have suggested mechanisms for back splicing, including insights from analyses of nascent RNA sequencing. In this review, we discuss our current understanding of back splicing regulation, and highlight its distinct characteristics in processing during nascent RNA synthesis by taking advantage of metabolic tagging nascent RNA sequencing. Features of recursive splicing are also discussed in the perspective of nascent RNA sequencing.

Keywords: 4sUDRB-seq; alternative splicing; back splicing; deep sequencing; metabolic tagging; nascent RNA-seq; recursive splicing; transcription.

Publication types

  • Review

MeSH terms

  • Gene Expression Profiling
  • Gene Expression Regulation / genetics*
  • Proteomics
  • RNA Precursors / genetics*
  • RNA Precursors / metabolism
  • RNA Splicing / genetics*
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • Sequence Analysis, RNA


  • RNA Precursors
  • RNA, Messenger