Isolation and characterization of the human tRNA-(N1G37) methyltransferase (TRM5) and comparison to the Escherichia coli TrmD protein.

A human TRM5 cDNA has been cloned and recombinant tRNA-N(1)G37 methyltransferase was produced. The recombinant enzyme methylates the N1 position of guanosine 37 (G37) in selected tRNA transcripts utilizing S-adenosyl methionine. The effects of RNA sequence and structure on the methylation reaction in comparison between the Escherichia coli TrmD and human TRM5 recombinant enzymes are presented.

Characterization of Streptococcus pneumoniae TrmD, a tRNA methyltransferase essential for growth.

Down-regulation of expression of trmD, encoding the enzyme tRNA (guanosine-1)-methyltransferase, has shown that this gene is essential for growth of Streptococcus pneumoniae. The S. pneumoniae trmD gene has been isolated and expressed in Escherichia coli by using a His-tagged T7 expression vector.

Towards understanding human mitochondrial leucine aminoacylation identity.

Specific recognition of tRNAs by aminoacyl-tRNA synthetases is governed by sets of aminoacylation identity elements, well defined for numerous prokaryotic systems and eukaryotic cytosolic systems. Only restricted information is available for aminoacylation of human mitochondrial tRNAs, despite their particularities linked to the non-classical structures of the tRNAs and their involvement in a growing number of human neurodegenerative disorders linked to mutations in the corresponding tRNA genes. A major difficulty to be overcome is the preparation of active in vitro transcripts enabling a rational mutagenic analysis, as is currently performed for classical tRNAs.

The 3' untranslated region of human vimentin mRNA interacts with protein complexes containing eEF-1gamma and HAX-1.

Previously, we have shown that the vimentin 3' untranslated region (3'UTR) contains a highly conserved region, which is sufficient for the perinuclear localization of a reporter mRNA. This region was shown to specifically bind protein(s) by band shift analyses. UV-cross-linking studies suggest these proteins are 46- and 35-kDa in mass.