Transfer RNA maturation in Chlamydomonas mitochondria, chloroplast and the nucleus by a single RN ase P protein

• Published in: The Plant journal : for cell and molecular biology 2016-08, Vol.87 (3), p.270-280
• Main Authors: Bonnard, Géraldine, Gobert, Anthony, Arrivé, Mathilde, Pinker, Franziska, Salinas‐Giegé, Thalia, Giegé, Philippe
• Format: Article
• Language: English
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.13198

The maturation of tRNA precursors involves the 5′ cleavage of leader sequences by an essential endonuclease called RN ase P. Beyond the ancestral ribonucleoprotein ( RNP ) RN ase P, a second type of RN ase P called PRORP (protein‐only RN ase P) evolved in eukaryotes. The current view on the distribution of RN ase P in cells is that multiple RNP s, multiple PRORP s or a combination of both, perform specialised RN ase P activities in the different compartments where gene expression occurs. Here, we identify a single gene encoding PRORP in the green alga Chlamydomonas reinhardtii while no RNP is found. We show that its product, Cr PRORP , is triple‐localised to mitochondria, the chloroplast and the nucleus. Its downregulation results in impaired tRNA biogenesis in both organelles and the nucleus. Cr PRORP , as a single‐subunit RN ase P for an entire organism, makes up the most compact and versatile RN ase P machinery described in either prokaryotes or eukaryotes. RN ase P removes 5′ leader sequences of tRNA precursors. Here we demonstrate that Chlamydomonas has a single RN ase P gene whose gene product acts in the chloroplast, mitochondria and the nucleus, thus contradicting the dogma that different RN ase P systems act in each of these cellular compartments.