The chloroplast RNA helicase ISE2 is required for multiple chloroplast RNA processing steps in Arabidopsis thalianaThe Plant Journal (2017)
INCREASED SIZE EXCLUSION LIMIT2 (ISE2) is a chloroplast-localized RNA helicase that is indispensable for
proper plant development. Chloroplasts in leaves with reduced ISE2 expression have previously been shown
to exhibit reduced thylakoid contents and increased stromal volume, indicative of defective development. It
has recently been reported that ISE2 is required for the splicing of group II introns from chloroplast transcripts.
The current study extends these findings, and presents evidence for ISE2’s role in multiple aspects
of chloroplast RNA processing beyond group II intron splicing. Loss of ISE2 from Arabidopsis thaliana leaves
resulted in defects in C-to-U RNA editing, altered accumulation of chloroplast transcripts and chloroplastencoded
proteins, and defective processing of chloroplast ribosomal RNAs. Potential ISE2 substrates were
identified by RNA immunoprecipitation followed by next-generation sequencing (RIP-seq), and the diversity
of RNA species identified supports ISE2’s involvement in multiple aspects of chloroplast RNA metabolism.
Comprehensive phylogenetic analyses revealed that ISE2 is a non-canonical Ski2-like RNA helicase that represents
a separate sub-clade unique to green photosynthetic organisms, consistent with its function as an
essential protein. Thus ISE2’s evolutionary conservation may be explained by its numerous roles in regulating
chloroplast gene expression.
Citation InformationKrzysztof Bobik, Tyra N McCray, Ben Ernest, Jessica C Fernandez, et al.. "The chloroplast RNA helicase ISE2 is required for multiple chloroplast RNA processing steps in Arabidopsis thaliana" The Plant Journal Vol. Online (2017) ISSN: 0960-7412
Available at: http://works.bepress.com/kate-howell/7/