Mitochondrially encoded tRNA proline also known as MT-TP is a transfer RNA that in humans is encoded by the mitochondrialMT-TPgene.[1]
Structure
The MT-TP gene is located on the p arm of the non-nuclear mitochondrial DNA at position 12 and it spans 68 base pairs.[2] The structure of a tRNA molecule is a distinctive folded structure which contains three hairpin loops and resembles a three-leafed clover.[3]
Function
MT-TP is a small 68 nucleotide RNA (human mitochondrial map position 15956-16023) that transfers the amino acid proline to a growing polypeptide chain at the ribosome site of protein synthesis during translation. MT-TP is responsible for coding the microsomal triglyceride transfer protein, which is required for the synthesis of beta-lipoproteins in the liver and intestine. Beta-lipoproteins are essential in fat, cholesterol, and fat-soluble vitamin transport from the intestine to the bloodstream for absorption.[4]
Clinical significance
Abetalipoproteinemia
Mutations in MT-TP have been associated with abetalipoproteinemia. Abetalipoproteinemia is an inherited disorder characterized by an impaired absorption of fats and certain vitamins from the diet. Mutations in MT-TP cause an impaired microsomal triglyceride transfer protein and lead to reduced or absent beta-lipoprotein. The dysfunction of the microsomal triglyceride transfer protein then results in
insufficient levels of fats, cholesterol, and vitamins, which are necessary for growth and development.[4] Therefore, clinical manifestations of abetalipoproteinemia include impaired weight gain and growth, failure to thrive, diarrhea, and steatorrhea. Mutations of GLY865TER,[5] SER590ILE,[6] ASN780TYR,[7] ARG540HIS,[8] IVS9AS,[9] and ARG215TER[10] of the MT-TP gene have been found in patients with the disease.
^Benayoun L, Granot E, Rizel L, Allon-Shalev S, Behar DM, Ben-Yosef T (April 2007). "Abetalipoproteinemia in Israel: evidence for a founder mutation in the Ashkenazi Jewish population and a contiguous gene deletion in an Arab patient". Molecular Genetics and Metabolism. 90 (4): 453–7. doi:10.1016/j.ymgme.2006.12.010. PMID17275380.
^Sharp D, Blinderman L, Combs KA, Kienzle B, Ricci B, Wager-Smith K, Gil CM, Turck CW, Bouma ME, Rader DJ (September 1993). "Cloning and gene defects in microsomal triglyceride transfer protein associated with abetalipoproteinaemia". Nature. 365 (6441): 65–9. Bibcode:1993Natur.365...65S. doi:10.1038/365065a0. PMID8361539. S2CID4334532.