Secondary structure of vertebrate telomerase RNA

Telomerase is a ribonucleoprotein enzyme that maintains telomere length by adding telomeric sequence repeats onto chromosome ends. The essential RNA c omponent of telomerase provides the template for telomeric repeat synthesis . To determine the secondary structure of vertebrate telomerase RNA, 32 new telomerase RNA genes were cloned and sequenced from a variety of vertebrat e species including 18 mammals, 2 birds, 1 reptile, 7 amphibians, and 4 fis hes. Using phylogenetic comparative analysis, we propose a secondary struct ure that contains four structural domains conserved in all vertebrates. Ten helical regions of the RNA are universally conserved while other regions v ary significantly in length and sequence between different classes of verte brates. The proposed vertebrate telomerase RNA structure displays a strikin gly similar topology to the previously determined ciliate telomerase RNA st ructure, implying an evolutionary conservation of the global architecture o f telomerase RNA.