Disease relevance of MT-TK

• The 3243A>G mutation in the MTTL1 (tRNA(Leu)) gene and the 8344A>G mutation in the MTTK (tRNA(Lys)) gene are the most common mutations found in mitochondrial encephalomyopathy, lactic acidosis with stroke-like episodes and myoclonic epilepsy associated with ragged-red fibers, respectively [1].

High impact information on MT-TK

• Using TTGE (temporal temperature-gradient gel electrophoresis) and sequence analyses of the entire mitochondrial genome, we identified a novel heteroplasmic mutation (8300T>C) in the tRNA(lys) gene (MTTK) from a patient with unexplained exercise intolerance [2].
• The prevalence of a 9-base-pair (bp) deletion between the mitochondrial cytochrome oxidase II (MTCOX*2) and lysine tRNA (MTTK) genes (region V) has been used to estimate the genetic relationships among Asian and Pacific populations [3].
• While in parts congruent to the plastid TRNK intron phylogeny, a higher divergence of some sequences in PRT1 and in the previously reported, non cpDNA dataset indicates that remnants of an older species stock persisted east of Wallace's line and on the Sunda Shelf [4].
• We found that the Leishmania RNA import complex (RIC) could enter human cells by a caveolin-1-dependent pathway, where it induced import of endogenous cytosolic tRNAs, including tRNA(Lys), and restored mitochondrial function in a cybrid harboring a mutant mt tRNA(Lys) (MT-TK) gene [5].

Biological context of MT-TK

• These results indicated that the phylogeny of the TRNK intron could not reflect true phylogenetic relationships [4].

Analytical, diagnostic and therapeutic context of MT-TK

• Sequence analysis of the cpDNA TRNK intron supports this hypothesis showing the species of the Malay Archipelago as neighbour group to the isolated species from Sri Lanka, the Seychelles, and Madagascar. Based on phylogenetic reconstructions an origin of recent Nepenthaceae in the Indian subcontinent is assumed [4].

References