title: The yeast telomerase RNA, TLC1, participates in two distinct modes of TLC1-TLC1 association processes in vivo.
abstract: Telomerase core enzyme minimally consists of the telomerase reverse transcriptase domain-containing protein (Est2 in budding yeast S. cerevisiae) and telomerase RNA, which contains the template specifying the telomeric repeat sequence synthesized. Here we report that in vivo, a fraction of S. cerevisiae telomerase RNA (TLC1) molecules form complexes containing at least two molecules of TLC1, via two separable modes: one requiring a sequence in the 3' region of the immature TLC1 precursor and the other requiring Ku and Sir4. Such physical TLC1-TLC1 association peaked in G1 phase and did not require telomere silencing, telomere tethering to the nuclear periphery, telomerase holoenzyme assembly, or detectable Est2-Est2 protein association. These data indicate that TLC1-TLC1 associations reflect processes occurring during telomerase biogenesis; we propose that TLC1-TLC1 associations and subsequent reorganization may be regulatory steps in telomerase enzymatic activation.
authors.affiliation: Department of Biochemistry and Biophysics, University of California , San Francisco, CA , United States.
authors.forename: Tet
authors.initials: T
authors.lastname: Matsuguchi
authors.affiliation: Department of Biochemistry and Biophysics, University of California , San Francisco, CA , United States.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Blackburn
keywords: Biogenesis; TLC1; Telomerase; Telomerase RNA; Yeast