A homozygous telomerase T-motif variant resulting in markedly reduced repeat addition processivity in siblings with Hoyeraal Hreidarsson syndrome

Abstract

Key Points Biallelic inheritance of a telomerase T-motif mutation selectively impairs repeat addition processivity and results in severe disease. Computational algorithms commonly used to predict the impact of variants on protein function have limited sensitivity with regard to hTERT.

Telomerase mutations in smokers with severe emphysema

“…The 10 μl direct primer-extension reaction contained 5 μM dTTP, 5 μM dATP, 5 μM dGTP, 0.165 μM α-32 P-dGTP (3,000 Ci/mmol, 10 mCi/ml, PerkinElmer), and 1 μM (TTAGGG) 3 DNA primer in 1× telomerase reaction buffer (50 mM Tris-HCl pH 8.3, 2 mM DTT, 0.5 mM MgCl 2 , and 1 mM spermidine). Comparable wild-type and mutant telomerase expression in transfected cells was confirmed by Western blotting for the FLAG-tagged TERT protein (anti-FLAG, clone M2, Sigma-Aldrich) and GAPDH (clone 6C5, Ambion) as an internal control (39). Comparable immunopurification efficiency was also confirmed by Northern blotting of TR extracted from immunopurified telomerase (40).…”

Familial pulmonary fibrosis

“…Mutations in other components of the telomerase complex have recently been described in association with pulmonary fibrosis (DKC1, TINF2) [26][27], or with cutaneous, haematological, neurological or gastrointestinal manifestations without pulmonary fibrosis (RTEL1, NOP10, NHP2, CTC1) [19][20]28]. The availability of rapid sequencing tools (new generation sequencing: NGS) which perform a simultaneous analysis of several genes should facilitate the diagnosis of these rare forms of telomeropathies.…”

“…Des mutations portants sur d'autres composants du complexe télomérase ont récemment été décrites en association avec une fibrose pulmonaire (DKC1, TINF2) [26][27] ou avec des manifestations cutanées, hématologiques, neurologiques ou gastro-intestinales sans fibrose pulmonaire (RTEL1, NOP10, NHP2, CTC1) justifiant de rechercher des mutations sur ces gènes chez ces patients [19][20]28]. La diffusion des outils de séquençage rapide (séquençage nouvelle génération : NGS), qui permettent l'analyse simultanée de plusieurs gènes, devrait faciliter le diagnostic de ces formes rares de téloméropathies.…”

Endogenous Telomerase Reverse Transcriptase N-Terminal Tagging Affects Human Telomerase Function at Telomeres In Vivo

“…Understanding the molecular basis for telomerase recruitment to and RAP at telomeres is highly relevant to telomere biology, as a subset of disease-associated mutations in TERT are specifically defective in RAP or impair recruitment (61)(62)(63). Currently, studies of these TERT mutants are limited by the need for overexpression of TERT to characterize their biochemical defects.…”