Cell Reports (Jul 2024)

Interface-guided phenotyping of coding variants in the transcription factor RUNX1

  • Kivilcim Ozturk,
  • Rebecca Panwala,
  • Jeanna Sheen,
  • Kyle Ford,
  • Nathan Jayne,
  • Andrew Portell,
  • Dong-Er Zhang,
  • Stephan Hutter,
  • Torsten Haferlach,
  • Trey Ideker,
  • Prashant Mali,
  • Hannah Carter

Journal volume & issue
Vol. 43, no. 7
p. 114436

Abstract

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Summary: Single-gene missense mutations remain challenging to interpret. Here, we deploy scalable functional screening by sequencing (SEUSS), a Perturb-seq method, to generate mutations at protein interfaces of RUNX1 and quantify their effect on activities of downstream cellular programs. We evaluate single-cell RNA profiles of 115 mutations in myelogenous leukemia cells and categorize them into three functionally distinct groups, wild-type (WT)-like, loss-of-function (LoF)-like, and hypomorphic, that we validate in orthogonal assays. LoF-like variants dominate the DNA-binding site and are recurrent in cancer; however, recurrence alone does not predict functional impact. Hypomorphic variants share characteristics with LoF-like but favor protein interactions, promoting gene expression indicative of nerve growth factor (NGF) response and cytokine recruitment of neutrophils. Accessible DNA near differentially expressed genes frequently contains RUNX1-binding motifs. Finally, we reclassify 16 variants of uncertain significance and train a classifier to predict 103 more. Our work demonstrates the potential of targeting protein interactions to better define the landscape of phenotypes reachable by missense mutations.

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