@article{c45dfc1a63974ab1aedd94df0f2850ed,
title = "TbRAP1 has an unusual duplex DNA binding activity required for its telomere localization and VSG silencing",
abstract = "Localization of Repressor Activator Protein 1 (RAP1) to the telomere is essential for its telomeric functions. RAP1 homologs either directly bind the duplex telomere DNA or interact with telomere-binding proteins. We find that Trypanosoma brucei RAP1 relies on a unique double-stranded DNA (dsDNA) binding activity to achieve this goal. T. brucei causes human sleeping sickness and regularly switches its major surface antigen, variant surface glycoprotein (VSG), to evade the host immune response. VSGs are monoallelically expressed from subtelomeres, and TbRAP1 is essential for VSG regulation. We identify dsDNA and single-stranded DNA binding activities in TbRAP1, which require positively charged 737RKRRR741 residues that overlap with TbRAP1's nuclear localization signal in the MybLike domain. Both DNA binding activities are electrostatics-based and sequence nonspecific. The dsDNA binding activity can be substantially diminished by phosphorylation of two 737RKRRR741-adjacent S residues and is essential for TbRAP1's telomere localization, VSG silencing, telomere integrity, and cell proliferation.",
author = "Marjia Afrin and Gaurav, {Amit Kumar} and Xian Yang and Xuehua Pan and Yanxiang Zhao and Bibo Li",
note = "Funding Information: We thank G. A. M. Cross for the VSG6 and VSG2 rabbit antibodies and K. Gull for the TAT-1 antibody. We thank R. Sandhu for generating the 5SA mutant construct. We thank A. Severson and G. V. Boerner and the Li lab members for the comments on the manuscript. Funding: This work is supported by an NIH R01 grant AI066095 (PI, to B.L.), an NIH S10 grant S10OD025252 (PI, to B.L.), a Research Grants Council GRF grant PolyU 151062/18M (PI, to Y.Z.), and a Research Grants Council AoE grant AoE/M-09/12 (PI, to Y.Z.). The publication cost is partly supported by GRHD at CSU. Author contributions: Conceptualization, B.L. and Y.Z.; methodology, B.L., Y.Z., and A.K.G.; investigation, all authors; writing-original draft, B.L.; writing-review and editing, B.L., Y.Z., M.A., and A.K.G.; funding acquisition, B.L. and Y.Z.; resources, B.L. and Y.Z.; supervision, B.L. and Y.Z. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors. Reagents generated in this study will be made available upon request, but we may require a payment and a completed materials transfer agreement if there is potential for commercial application. Data and code availability: The RNAseq data generated during this study are available at GEO repository (GSE147734). Publisher Copyright: Copyright {\textcopyright} 2020 The Authors, some rights reserved.",
year = "2020",
month = sep,
doi = "10.1126/sciadv.abc4065",
language = "English",
volume = "6",
journal = "Science advances",
issn = "2375-2548",
publisher = "American Association for the Advancement of Science",
number = "38",
}
