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Updated: May 21, 2026

Semi-quantitative Detection of RNA-dependent RNA Polymerase Activity of Human Telomerase Reverse Transcriptase Protein
Published on: June 12, 2018
Structural basis for telomerase RNA recognition and RNP assembly by the holoenzyme La family protein p65
Mahavir Singh1, Zhonghua Wang, Bon-Kyung Koo
1Department of Chemistry, and the Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095-1569, USA.
Abstract:
Telomerase is a ribonucleoprotein complex essential for maintenance of telomere DNA at linear chromosome ends. The catalytic core of Tetrahymena telomerase comprises a ternary complex of telomerase RNA (TER), telomerase reverse transcriptase (TERT), and the essential La family protein p65. NMR and crystal structures of p65 C-terminal domain and its complex with stem IV of TER reveal that RNA recognition is achieved by a combination of single- and double-stranded RNA binding, which induces a 105° bend in TER. The domain is a cryptic, atypical RNA recognition motif with a disordered C-terminal extension that forms an α helix in the complex necessary for hierarchical assembly of TERT with p65-TER. This work provides the first structural insight into biogenesis and assembly of TER with a telomerase-specific protein. Additionally, our studies define a structurally homologous domain (xRRM) in genuine La and LARP7 proteins and suggest a general mode of RNA binding for biogenesis of their diverse RNA targets.
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