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Jiang, Hui
Publications (4 of 4) Show all publications
Jiang, H., Xue, X., Panda, S., Kawale, A., Hooy, R. M., Liang, F., . . . Gekara, N. O. (2019). Chromatin-bound cGAS is an inhibitor of DNA repair and hence accelerates genome destabilization and cell death. EMBO Journal, 38(21), Article ID e102718.
Open this publication in new window or tab >>Chromatin-bound cGAS is an inhibitor of DNA repair and hence accelerates genome destabilization and cell death
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2019 (English)In: EMBO Journal, ISSN 0261-4189, E-ISSN 1460-2075, Vol. 38, no 21, article id e102718Article in journal (Refereed) Published
Abstract [en]

DNA repair via homologous recombination (HR) is indispensable for genome integrity and cell survival but if unrestrained can result in undesired chromosomal rearrangements. The regulatory mechanisms of HR are not fully understood. Cyclic GMP‐AMP synthase (cGAS) is best known as a cytosolic innate immune sensor critical for the outcome of infections, inflammatory diseases, and cancer. Here, we report that cGAS is primarily a chromatin‐bound protein that inhibits DNA repair by HR, thereby accelerating genome destabilization, micronucleus generation, and cell death under conditions of genomic stress. This function is independent of the canonical STING‐dependent innate immune activation and is physiologically relevant for irradiation‐induced depletion of bone marrow cells in mice. Mechanistically, we demonstrate that inhibition of HR repair by cGAS is linked to its ability to self‐oligomerize, causing compaction of bound template dsDNA into a higher‐ordered state less amenable to strand invasion by RAD51‐coated ssDNA filaments. This previously unknown role of cGAS has implications for understanding its involvement in genome instability‐associated disorders including cancer.

Place, publisher, year, edition, pages
EMBOpress, 2019
Keywords
cancer, cell death, cGAS, chromatin compaction, DNA repair
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-164894 (URN)10.15252/embj.2019102718 (DOI)000487392000001 ()31544964 (PubMedID)
Funder
Swedish Research Council, 2015-02857Swedish Research Council, 2016-00890Swedish Cancer Society, CAN 2017/421NIH (National Institute of Health), R01 CA220123NIH (National Institute of Health), P30 CA054174NIH (National Institute of Health), R01 GM GM 129342-01-A1
Available from: 2019-11-06 Created: 2019-11-06 Last updated: 2019-11-26Bibliographically approved
Jiang, H., Panda, S. & Gekara, N. O. (2019). Comet and micronucleus assays for analyzing DNA damage and genome integrity. In: Sohn, J (Ed.), DNA SENSORS AND INFLAMMASOMES: (pp. 299-307). ELSEVIER ACADEMIC PRESS INC
Open this publication in new window or tab >>Comet and micronucleus assays for analyzing DNA damage and genome integrity
2019 (English)In: DNA SENSORS AND INFLAMMASOMES / [ed] Sohn, J, ELSEVIER ACADEMIC PRESS INC , 2019, p. 299-307Chapter in book (Refereed)
Abstract [en]

Detection of DNA damage in cells is fundamental for the study of DNA repair and genome-instability associated processes including carcinogenesis. Many studies often rely on cytotoxicity assays to estimate genotoxicity. However, measurements of cytotoxicity, a delayed outcome requiring high threshold genotoxicity to induce, does not provide information about the subtle, early genotoxic effects relevant for mechanistic understanding of DNA repair processes. Here describe how to combine two simple procedures for monitoring the presence of DNA damage in individual eukaryotic cells using: (1) the Comet assay for measuring initial DNA breaks and (2) the Micronucleus assay for detecting delayed outcome DNA breaks in dividing cells. We discuss the principles, experimental design considerations and troubleshooting tips for optimizing these methods. They require standard molecular biology instruments and a fluorescent microscope.

Place, publisher, year, edition, pages
ELSEVIER ACADEMIC PRESS INC, 2019
Series
Methods in Enzymology, ISSN 0076-6879 ; 625
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-164490 (URN)10.1016/bs.mie.2019.05.015 (DOI)000488782900019 ()31455533 (PubMedID)978-0-12-818360-1 (ISBN)978-0-12-818359-5 (ISBN)
Available from: 2019-10-25 Created: 2019-10-25 Last updated: 2019-10-25Bibliographically approved
Gekara, N. O. & Jiang, H. (2019). The innate immune DNA sensor cGAS: A membrane, cytosolic, or nuclear protein?. Science Signaling, 12(581), Article ID eaax3521.
Open this publication in new window or tab >>The innate immune DNA sensor cGAS: A membrane, cytosolic, or nuclear protein?
2019 (English)In: Science Signaling, ISSN 1945-0877, E-ISSN 1937-9145, Vol. 12, no 581, article id eaax3521Article in journal, Editorial material (Other academic) Published
Abstract [en]

Cyclic cGMP-AMP synthase (cGAS) alerts the innate immune system to the presence of foreign or damaged self-DNA inside the cell and is critical for the outcome of infections, inflammatory diseases, and cancer. Two studies now demonstrate that cGAS activation is regulated by differential subcellular localization through its non-enzymatic, N-terminal domain.

Place, publisher, year, edition, pages
Washington: American Association for the Advancement of Science, 2019
National Category
Cell Biology
Identifiers
urn:nbn:se:umu:diva-159599 (URN)10.1126/scisignal.aax3521 (DOI)000467963000003 ()31088977 (PubMedID)
Available from: 2019-06-17 Created: 2019-06-17 Last updated: 2019-06-17Bibliographically approved
Panda, S., Jiang, H. & Gekara, N. O. (2019). TUBE and UbiCRest assays for elucidating polyubiquitin modifications in protein complexes. In: Sohn, J (Ed.), DNA SENSORS AND INFLAMMASOMES: (pp. 339-350). ELSEVIER ACADEMIC PRESS INC
Open this publication in new window or tab >>TUBE and UbiCRest assays for elucidating polyubiquitin modifications in protein complexes
2019 (English)In: DNA SENSORS AND INFLAMMASOMES / [ed] Sohn, J, ELSEVIER ACADEMIC PRESS INC , 2019, p. 339-350Chapter in book (Refereed)
Abstract [en]

Ubiquitination is a reversible posttranslational modification that regulates nearly all cellular processes. The ubiquitin polypeptide is conjugated via its C-terminus to amine groups of lysine residues on target protein. Additionally, ubiquitins moieties can be conjugated in tandem to the initial ubiquitin via any of its internal lysine residues or N terminal methionine residue, resulting in the formation of polyubiquitin chains with distinct biophysical properties and biological functions. Elucidating the types of polyubiquitin chains present in proteins is essential for understanding their function and mechanism of regulation. Traditionally, ubiqutin modifications have been elucidated by exogenously co-expressing proteins of interest with epitope-tagged ubiquitins mutated in specific lysine residues. However, this strategy is prone experimental artifacts. In this protocol, we describe how to elucidate endogenous ubiquitin modifications. This procedure combines TUBE (Tandem Ubiquitin Binding Entity)-based isolation of ubiquitin conjugates, digestion with linkage specific deubiquitinases and immunoblotting. This procedure is very robust can be applied to profile types and architectural organization polyubiquitin chains present on the any proteins of interest and has been instrumental in elucidating ubiquitin modifications in NOD2 signaling in our recent study (Panda & Gekara, 2018).

Place, publisher, year, edition, pages
ELSEVIER ACADEMIC PRESS INC, 2019
Series
Methods in Enzymology, ISSN 0076-6879 ; 625
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-164489 (URN)10.1016/bs.mie.2019.05.006 (DOI)000488782900021 ()31455535 (PubMedID)978-0-12-818360-1 (ISBN)978-0-12-818359-5 (ISBN)
Available from: 2019-10-25 Created: 2019-10-25 Last updated: 2019-10-25Bibliographically approved
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