What is "mt-tf"

Mitochondrially encoded tRNA phenylalanine also known as MT-TF is a transfer RNA which in humans is encoded by the mitochondrial MT-TF gene.

MT-TF is a small 71 nucleotide RNA (human mitochondrial map position 577-647) that transfers the amino acid phenylalanine to a growing polypeptide chain at the ribosome site of protein synthesis during translation.