Identification of modulators of the ALT pathway through a native FISH-based optical screen

Benura Azeroglu; Simran Khurana; Shih-Chun Wang; Gianna M Tricola; Shalu Sharma; Camille Jubelin; Ylenia Cortolezzis; Gianluca Pegoraro; Kyle M Miller; Travis H Stracker; Eros Lazzerini Denchi

doi:10.1016/j.celrep.2024.115114

Identification of modulators of the ALT pathway through a native FISH-based optical screen

Cell Rep. 2024 Dec 26;44(1):115114. doi: 10.1016/j.celrep.2024.115114. Online ahead of print.

Affiliations

¹ Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
² Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
³ Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA.
⁴ Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Department of Medicine, Università degli Studi di Udine, 33100 Udine, Italy.
⁵ High-Throughput Imaging Facility, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
⁶ Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address: [email protected].
⁷ Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address: [email protected].

PMID: 39729394
DOI: 10.1016/j.celrep.2024.115114

Abstract

A significant portion of human cancers utilize a recombination-based pathway, alternative lengthening of telomeres (ALT), to extend telomeres. To gain further insights into this pathway, we developed a high-throughput imaging-based screen named TAILS (telomeric ALT in situ localization screen) to identify genes that either promote or inhibit ALT activity. Screening over 1,000 genes implicated in DNA transactions, TAILS reveals both well-established and putative ALT modulators. Here, we present the validation of factors that promote ALT, such as the nucleosome-remodeling factor CHD4 and the chromatin reader SGF29, as well as factors that suppress ALT, including the RNA helicases DExD-box helicase 39A/B (DDX39A/B), the replication factor TIMELESS, and components of the chromatin assembly factor CAF1. Our data indicate that defects in histone deposition significantly contribute to ALT-associated phenotypes. Based on these findings, we demonstrate that pharmacological treatments can be employed to either exacerbate or suppress ALT-associated phenotypes.

Keywords: ALT; CP: Molecular biology; DDX39A; histone deposition; ssTelo; telomeres.

Published by Elsevier Inc.