The telomerase reverse transcriptase (TERT) is the essential protein component of the telomerase ribonucleoprotein. TERT is composed of three domains, a central RT domain where nucleotide transfer occurs, N-terminal extension (NTE) that contains RNA-interaction domains 1 and 2 (RID1 and RID2), and C-terminal extension (CTE) for processivity and localization. The reverse transcriptase is less divergent than the RNA component of telomerase. Below are details on the TERT sequences, the scientific and common name where applicable, the length and GC content for the cDNA; the length, the isoelectric point (pKI), the molecular weight, and the sequence (.seq button) for the amino acid sequences; the genbank accession numbers are linked to the record at the National Center for Biotechnology Information (NCBI), and original literature citations that are linked to the published online journal. The sequences are organized by taxon.