7cuj
From Proteopedia
Crystal structure of fission yeast Ccq1 and Tpz1
Structural highlights
Function[CCQ1_SCHPO] Component of the meiotic bouquet that facilitates meiotic nuclear reorganization of the telomeres to the centrosome. Links telomeres to the meiotic centrosome component pcp1. Essential for the formation of normal telomere clusters during meiotic prophase. Required for telomere length regulation and chromosome segregation. Required for proper positioning of nucleosomes at heterochromatic loci and for transcriptional gene silencing (TGS) function of the Snf2/Hdac-containing repressor complex (SHREC).[1] [2] [3] Publication Abstract from PubMedThe conserved shelterin complex caps chromosome ends to protect telomeres and regulate telomere replication. In fission yeast Schizosaccharomyces pombe, shelterin consists of telomeric single- and double-stranded DNA-binding modules Pot1-Tpz1 and Taz1-Rap1 connected by Poz1, and a specific component Ccq1. While individual structures of the two DNA-binding OB folds of Pot1 (Pot1OB1-GGTTAC and Pot1OB2-GGTTACGGT) are available, structural insight into recognition of telomeric repeats with spacers by the complete DNA-binding domain (Pot1DBD) remains an open question. Moreover, structural information about the Tpz1-Ccq1 interaction requires to be revealed for understanding how the specific component Ccq1 of S. pombe shelterin is recruited to telomeres to function as an interacting hub. Here, we report the crystal structures of Pot1DBD-single-stranded-DNA, Pot1372-555-Tpz1185-212 and Tpz1425-470-Ccq1123-439 complexes and propose an integrated model depicting the assembly mechanism of the shelterin complex at telomeres. The structure of Pot1DBD-DNA unveils how Pot1 recognizes S. pombe degenerate telomeric sequences. Our analyses of Tpz1-Ccq1 reveal structural basis for the essential role of the Tpz1-Ccq1 interaction in telomere recruitment of Ccq1 that is required for telomere maintenance and telomeric heterochromatin formation. Overall, our findings provide valuable structural information regarding interactions within fission yeast shelterin complex at 3' ss telomeric overhang. Structural insights into Pot1-ssDNA, Pot1-Tpz1 and Tpz1-Ccq1 Interactions within fission yeast shelterin complex.,Sun H, Wu Z, Zhou Y, Lu Y, Lu H, Chen H, Shi S, Zeng Z, Wu J, Lei M PLoS Genet. 2022 Jul 18;18(7):e1010308. doi: 10.1371/journal.pgen.1010308., eCollection 2022 Jul. PMID:35849625[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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