Two independent regions of human telomerase reverse transcriptase are important for its oligomerization and telomerase activity

Kuniaki Arai, Kenkichi Masutomi, Shilagardy Khurts, Shuichi Kaneko, Kenichi Kobayashi, Seishi Murakami

Research output: Contribution to journalArticle

Abstract

Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, contains motifs conserved among reverse transcriptases. Several nucleic acid-dependent polymerases that share a "fingers, palm, and thumb substructure" were shown to oligomerize. Here we demonstrate that hTERT also has this ability using partially purified recombinant hTERTs and mammalian cells co-expressing differently tagged hTERTs. Human template RNA (hTR), by contrast, has no effect on the structural oligomerization of hTERTs. Therefore, hTERT has an intrinsic ability of oligomerization in the absence of hTR. We identified two separate regions as essential for the oligomerization. The regions, amino acids 301-538 (amino-terminal region) and amino acids 914-928 (carboxyl-terminal region), are outside the fingers and palm substructure covering motif T to D and interact with each other in vivo. A substituted mutant of hTERT, hTERT-D712A-V7131, which was reported as a dominant negative form of hTERT, bound to the wildtype hTERT and inhibited its telomerase activity transiently expressed in telomerase-negative finite normal human fibroblast. The truncated forms of hTERT containing the binding region to the wild-type hTERT partially inhibited the telomerase activity, probably by preventing the wild-type hTERT from forming an oligomer. Taken together, the oligomerization of hTERT is an important step for telomerase activity.

Original languageEnglish (US)
Pages (from-to)8538-8544
Number of pages7
JournalJournal of Biological Chemistry
Volume277
Issue number10
DOIs
StatePublished - Mar 8 2002
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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