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Intracellular localization and induction of a dynamic RNA ‐editing event of macro‐algal V‐ATP ase subunit A ( VHA‐A ) in response to copper
Author(s) -
MORRIS C. A.,
OWEN J. R.,
THOMAS M. C.,
ELHITI G. A.,
HARWOOD J. L.,
KILLE P.
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12145
Subject(s) - protein subunit , rna , messenger rna , intracellular , biology , riboswitch , biochemistry , microbiology and biotechnology , chemistry , gene , non coding rna
A V‐ATP ase subunit A protein ( VHA ‐ A ) transcript together with a variant ( C 793 to U ), which introduces a stop codon truncating the subunit immediately downstream of its ATP binding site, was identified within a F ucus vesiculosus cDNA from a heavy metal contaminated site. This is intriguing because the VHA‐A subunit is the crucial catalytic subunit responsible for the hydrolysis of ATP that drives ion transport underlying heavy metal detoxification pathways. We employed a chemiluminescent hybridization protection assay to quantify the proportion of both variants directly from mRNA while performing quantification of total transcript using Q‐PCR . Polyclonal antisera raised against recombinant VHA‐A facilitated simultaneous detection of parent and truncated VHA‐A and revealed its cellular and subcellular localization. By exploiting laboratory exposures and samples from an environmental copper gradient, we showed that total VHA ‐ A transcript and protein, together with levels of the truncated variant, were induced by copper. The absence of a genomic sequence representing the truncated variant suggests a RNA editing event causing the production of the truncated VHA‐A . Based on these observations, we propose RNA editing as a novel molecular process underpinning VHA trafficking and intracellular sequestration of heavy metals under stress.