Models for human telomere C-strand fill-in by CST-Pol α-primase

Trends Biochem Sci. 2023 Aug 15:S0968-0004(23)00174-3. doi: 10.1016/j.tibs.2023.07.008. Online ahead of print.ABSTRACTTelomere maintenance is essential for the genome integrity of eukaryotes, and this function is underpinned by the two-step telomeric DNA synthesis process: telomere G-overhang extension by telomerase and complementary strand fill-in by DNA polymerase alpha-primase (polα-primase). Compared to the telomerase step, the telomere C-strand fill-in mechanism is less understood. Recent studies have provided new insights into how telomeric single-stranded DNA-binding protein CTC1-STN1-TEN1 (CST) and polα-primase coordinate to synthesize the telomeric C-strand for telomere overhang fill-in. Cryogenic electron microscopy (cryo-EM) structures of CST-polα-primase complexes have provided additional insights into how they assemble at telomeric templates and de novo synthesize the telomere C-strand. In this review, we discuss how these latest findings coalesce with existing understanding to develop a human telomere C-strand fill-in mechanism model.PMID:37586999 | DOI:10.1016/j.tibs.2023.07.008

Source: Trends in Biochemical Sciences - August 16, 2023 Category: Biochemistry Authors: Qixiang He Ci Ji Lim Source Type: research