The chloroplastic DEVH-box RNA helicase INCREASED SIZE EXCLUSION LIMIT 2 involved in plasmodesmata regulation is required for group II intron splicing

Plant Cell Environ. 2016 Jan;39(1):165-73. doi: 10.1111/pce.12603. Epub 2015 Sep 19.


INCREASED SIZE EXCLUSION LIMIT 2 (ISE2) encodes a putative DEVH-box RNA helicase originally identified through a genetic screening for Arabidopsis mutants altered in plasmodesmata (PD) aperture. Depletion of ISE2 also affects chloroplasts activity, decreases accumulation of photosynthetic pigments and alters expression of photosynthetic genes. In this work, we show the chloroplast localization of ISE2 and decipher its role in plastidic RNA processing and, consequently, PD function. Group II intron-containing RNAs from chloroplasts exhibit defective splicing in ise2 mutants and ISE2-silenced plants, compromising plastid viability. Furthermore, RNA immunoprecipitation suggests that ISE2 binds in vivo to several splicing-regulated RNAs. Finally, we show that the chloroplast clpr2 mutant (defective in a subunit of a plastidic Clp protease) also exhibits abnormal PD function during embryogenesis, supporting the idea that chloroplast RNA processing is required to regulate cell-cell communication in plants.

Keywords: Retrograde signals; cell-to-cell communication; chloroplast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Biological Transport
  • Chloroplasts / enzymology
  • DEAD-box RNA Helicases / genetics
  • DEAD-box RNA Helicases / metabolism
  • Gene Expression Regulation, Plant*
  • Genes, Reporter
  • Introns / genetics
  • Mutation
  • Photosynthesis
  • Plants, Genetically Modified
  • Plasmodesmata / metabolism*
  • RNA Helicases / genetics*
  • RNA Helicases / metabolism
  • RNA Splicing*
  • RNA, Chloroplast / genetics
  • RNA, Chloroplast / metabolism
  • Seedlings / drug effects
  • Seedlings / enzymology
  • Seedlings / genetics
  • Seedlings / metabolism


  • Arabidopsis Proteins
  • RNA, Chloroplast
  • INCREASED SIZE EXCLUSION LIMIT2 protein, Arabidopsis
  • DEAD-box RNA Helicases
  • RNA Helicases