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n MAT 4, a maturase factor required for nad1 pre‐m RNA processing and maturation, is essential for holocomplex I biogenesis in A rabidopsis mitochondria
Author(s) -
Cohen Sigal,
Zmudjak Michal,
Colas des FrancsSmall Catherine,
Malik Sunita,
Shaya Felix,
Keren Ido,
Belausov Eduard,
Many Yair,
Brown Gregory G.,
Small Ian,
OstersetzerBiran Oren
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12466
Subject(s) - group ii intron , intron , biology , rna splicing , arabidopsis , splicing factor , genetics , gene , trans splicing , rna , alternative oxidase , microbiology and biotechnology , mutant
Summary Group II introns are large catalytic RNA s that are found in bacteria and organellar genomes of lower eukaryotes, but are particularly prevalent within mitochondria in plants, where they are present in many critical genes. The excision of plant mitochondrial introns is essential for respiratory functions, and is facilitated in vivo by various protein cofactors. Typical group II introns are classified as mobile genetic elements, consisting of the self‐splicing ribozyme and its own intron‐encoded maturase protein. A hallmark of maturases is that they are intron‐specific, acting as cofactors that bind their intron‐containing pre‐ RNA s to facilitate splicing. However, the degeneracy of the mitochondrial introns in plants and the absence of cognate intron‐encoded maturase open reading frames suggest that their splicing in vivo is assisted by ‘ trans ’‐acting protein factors. Interestingly, angiosperms harbor several nuclear‐encoded maturase‐related ( n M at ) genes that contain N ‐terminal mitochondrial localization signals. Recently, we established the roles of two of these paralogs in A rabidopsis, n MAT 1 and n MAT 2, in the splicing of mitochondrial introns. Here we show that n MAT 4 ( A t1g74350) is required for RNA processing and maturation of nad1 introns 1, 3 and 4 in Arabidopsis mitochondria. Seed germination, seedling establishment and development are strongly affected in homozygous nmat4 mutants, which also show modified respiration phenotypes that are tightly associated with complex I defects.