TRNT1 : tRNA nucleotidyl transferase 1
Description
The TRNT1 (tRNA nucleotidyl transferase 1) is a protein-coding gene located on chromosome 3.
The TRNT1 gene provides instructions for making a protein involved in the production (synthesis) of other proteins. During protein synthesis, a molecule called transfer RNA (tRNA) helps assemble protein building blocks (amino acids) into a chain that forms the protein. Each tRNA carries a specific amino acid to the growing chain. The TRNT1 protein modifies tRNAs by adding a series of three DNA building blocks (nucleotides), called a CCA trinucleotide, to the molecule. This modification is essential for the correct amino acid to be attached to each tRNA.While most protein synthesis occurs in the fluid surrounding the nucleus (cytoplasm), some proteins are synthesized in cell structures called mitochondria, which are the energy-producing centers in cells. Many mitochondrial proteins form groups (complexes) that carry out the reactions that produce energy. Separate tRNA molecules are used to build proteins in the cytoplasm and mitochondria. The TRNT1 protein attaches the CCA trinucleotide to both cytoplasmic and mitochondrial tRNA molecules.
TRNT1 is a nucleotidyltransferase that adds and repairs the essential CCA sequence at the 3' end of tRNA molecules. This sequence is crucial for attaching amino acids to tRNA, which is a key step in protein synthesis. TRNT1 uses CTP and ATP as substrates to carry out this process. TRNT1 also plays a role in tRNA processing and repair, ensuring that tRNA molecules are functional. It promotes tRNA recycling by adding the CCA sequence to tRNA molecules that have been cleaved by ANKZF1 and repaired by ELAC1. TRNT1 is involved in tRNA surveillance by adding a CCACCA sequence to the 3' end of unstable tRNA molecules, which targets them for degradation. This process ensures that only functional tRNA molecules are used in protein synthesis. Stable tRNAs receive only 3'-terminal CCA, while unstable tRNAs beginning with GG are marked with CCACCA and degraded. TRNT1's structural flexibility allows it to differentiate between stable and unstable tRNAs. Following the first CCA addition cycle, binding of nucleotides to the active site triggers a clockwise screw motion, producing torque on the RNA. This ejects stable RNAs, while unstable RNAs are refolded while bound to the enzyme and subjected to a second CCA catalytic cycle.
TRNT1 is also known as CCA1, CGI-47, MtCCA, RPEM, SIFD.
Associated Diseases
- Retinitis pigmentosa and erythrocytic microcytosis
- Sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay
- TRNT1 deficiency
