The structural organization and arrangement of both genomes consisted of 13 typical vertebrate protein-coding genes, 22 transfer RNA (
tRNA) genes, 2 ribosomal RNA (rRNA) genes and one putative control region (Fig.
As per researchers involved in this study, which was published in the 'Journal of Clinical Investigation',
tRNAs are cut into fragments when cells are stressed.
Using blood samples from people with the condition at the Epilepsy Monitoring Unit in Dublin's Beaumont Hospital and a similar specialist centre in Germany, the group found fragment levels of three
tRNAs "spike" in the blood hours before a seizure.
We created a subalignment of
tRNA data with 319 aligned positions and 43 taxa to minimize missing data for genetic distance analyses.
Putative
tRNA genes were identified using tRNAscan-SE v2.0 (http://lowelab.ucsc.edu/tRNAscan-SE; Lowe & Chan 2016) and ARWEN (http://mbio-serv2.
Another shortcoming is that the authors describe the variant as being located in the
tRNA (Glu) gene on the one hand and on the other hand as being located in the mitochondrial NADH dehydrogenase subunit 6gene.
The mRNA is essentially a string of genetic "letters" spelling out protein-making instructions, and each
tRNA recognizes a specific three-letter sequence on the mRNA.
In one study, (23) Rando found that the offspring of protein-deprived mice had altered cholesterol synthesis in the liver, a finding he attributes to
tRNA fragment activity.
Characteristic features include Raynaud phenomenon, fever, nonerosive inflammatory arthritis, hyperkeratotic skin changes on the fingers ("mechanic's hands"), interstitial lung disease (ILD), and autoantibodies to various
tRNA synthetases.
Although the presence of the chemical modifications to
tRNA has been established in the 1970s [6-8], little is known about the epigenetic modifications to mRNA and other noncoding RNAs.
Mitochondrial (mt)
tRNA (MTT) gene mutations are an important cause of mitochondrial diseases and are associated with a wide range of clinical presentations, ranging from isolated myopathy to multisystem disorders with encephalopathy, diabetes, hearing loss, dysphagia, and cardiomyopathy [1].
Interestingly, amongst the seven genes that have been identified to cause the disease, most have housekeeping functions, including small heat shock proteins (sHSP) (dHMN-II); glycyl
tRNA synthetase (GARS) (dHMN-V); Berardinelli-Seip congenital lipodystrophy (BSCL2) (dHMN-V); immunoglobulin [micro]-binding protein-2 (IGHMBP2) (dHMN-VI); dynactin (DCTN1) (dHMN-VII); and senataxin (SETX) (dHMN) with pyramidal tract signs.