TPP1 mutagenesis screens unravel shelterin interfaces and functions in hematopoiesis
| Autor: | Ann Friedman, Frederick Allen, Sherilyn Grill, Ivan Maillard, Shilpa Padmanaban, Jennifer Chase, Jayakrishnan Nandakumar, Valerie M. Tesmer, Rami Khoriaty, Catherine E. Keegan, Eric Perkey |
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| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Telomerase Cell Survival Telomere-Binding Proteins Mutant Mutagenesis (molecular biology technique) Biology Cellular senescence Shelterin Complex Mice 03 medical and health sciences 0302 clinical medicine Genetics Animals Humans Telomeric Repeat Binding Protein 2 Bone marrow Gene Hematology General Medicine Hematopoietic Stem Cells Shelterin Phenotype Hematopoiesis Telomere Cell biology Telomeres 030104 developmental biology 030220 oncology & carcinogenesis Mutagenesis Site-Directed Medicine Stem cell Research Article |
| Zdroj: | JCI Insight, Vol 6, Iss 9 (2021) JCI Insight |
| ISSN: | 2379-3708 |
| Popis: | Telomerase catalyzes chromosome end replication in stem cells and other long-lived cells. Mutations in telomerase or telomere-related genes result in diseases known as telomeropathies. Telomerase is recruited to chromosome ends by the ACD/TPP1 protein (TPP1 hereafter), a component of the shelterin complex that protects chromosome ends from unwanted end joining. TPP1 facilitates end protection by binding shelterin proteins POT1 and TIN2. TPP1 variants have been associated with telomeropathies but remain poorly characterized in vivo. Disease variants and mutagenesis scans provide efficient avenues to interrogate the distinct physiological roles of TPP1. Here, we conduct mutagenesis in the TIN2- and POT1-binding domains of TPP1 to discover mutations that dissect TPP1’s functions. Our results extend current structural data to reveal that the TPP1-TIN2 interface is more extensive than previously thought and highlight the robustness of the POT1-TPP1 interface. Introduction of separation-of-function mutants alongside known TPP1 telomeropathy mutations in mouse hematopoietic stem cells (mHSCs) lacking endogenous TPP1 demonstrated a clear phenotypic demarcation. TIN2- and POT1-binding mutants were unable to rescue mHSC failure resulting from end deprotection. In contrast, TPP1 telomeropathy mutations sustained mHSC viability, consistent with their selectively impacting end replication. These results highlight the power of scanning mutagenesis in revealing structural interfaces and dissecting multifunctional genes. |
| Databáze: | OpenAIRE |
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