Tissue Specific Expression Studies of Nuclear Maturases in A. thaliana

Abstract

Post-transcriptional processes play a crucial role in the regulation of gene expression. In general, such regulatory processes are regulated by binding of specific proteins to structures present on some mRNA or pre-mRNAs but not others. Post transcriptional regulatory processes are particularly prevalent in plant mitochondria. The removal of group II introns from plant mtDNA is essential for normal function of mitochondria, and thus respiration. Intron encoded maturases are proteins which facilitate self splicing of group II introns in bacteria and organellar genomes of several lower eukaryotes. Plant organelles also contain group II introns, but have lost maturase ORF. Nuclear maturases (nMATs) are the proteins encoded by nuclear genes of angiosperms.  The four nMAT proteins are classified as nMAT1, nMAT2, nMAT3, and nMAT4. nMATs are transported to mitochondria for specific and efficient splicing of group II introns of mitochondria encoded genes. The roles of three of these paralogs in Arabidopsis (nMAT1, nMAT2, and nMAT4) in the splicing of mitochondrial introns have been established. Deficiency of these proteins in nmat mutants causes embryo-defective and developmentally delayed phenotypes. Present study shows that all four NMATs are transcribed in flower, silique, root, cotyledon, hypocotyl, rosette leaf tissue at various degrees for different genes, with highest in flower and silique tissue for all nMATs.