Identification of Novel Modulators of the ALT Pathway Through a Native FISH-Based Optical Screen

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• Alternative Lengthening of Telomeres (ALT) is a key mechanism for telomere maintenance in a significant fraction of human cancers.
• Understanding the regulation of ALT is critical for developing targeted cancer therapies.

Purpose of the Study:

• To identify novel genes that modulate Alternative Lengthening of Telomeres (ALT) activity.
• To investigate the role of chromatin and DNA transaction factors in ALT regulation.

Main Methods:

• Development and application of a high-throughput imaging-based screen, TAILS (Telomeric ALT In situ Localization Screen).
• Screening of over 1000 genes involved in DNA transactions to identify ALT modulators.
• Functional validation of identified genes in promoting or suppressing ALT.

Main Results:

• Identification of novel ALT-promoting factors, including CHD4 and SGF29.
• Discovery of ALT-suppressing factors, such as DDX39A/B, TIMELESS, and CAF1 components.
• Demonstration that defects in histone deposition are linked to ALT-associated phenotypes.

Conclusions:

• The TAILS screen successfully identified novel regulators of ALT.
• Histone deposition plays a significant role in ALT-associated phenotypes.
• Pharmacological modulation of ALT activity is feasible, offering potential therapeutic strategies.