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in regulating double strand break repair or the DDR response to transcriptional by-products . In this
study we examine the role of the transcription termination factor Xrn2 in the DNA damage response. Xrn2
is a 5’-3’ ribo-exonuclease involved in several RNA degradation pathways 10-12 . We find that Xrn2 responds
by undergoing nuclear re-localization in response to multiple forms of DNA damage and co-localizes with
transcriptional by-products, in particular RNA:DNA hybrids (R-loops). We find that loss of Xrn2 leads to
increased sensitivity to several forms of DNA damaging lesions and increased genomic instability. Loss of
Xrn2 also leads to increased amounts of replication stress and R-loop formation. We also find that the
nuclear re-localization of Xrn2 is dependent on active transcription and R-loop formation. Loss of Xrn2
also leads to delayed DNA damage repair kinetics in response to ionizing radiation. Importantly, we find
that the difference in DNA repair kinetics in cells that have lost Xrn2 is due to active transcription and
formation of R-loops. This suggest that Xrn2 is involved in regulating transcription after DNA damage and
that this regulation is important for repairing double strand breaks in a timely manner. 1 Kim, N. & Jinks-
Robertson, S. Transcription as a source of genome instability. Nat Rev Genet 13, 204-214 (2012). 2
Aguilera, A. & García-Muse, T. R Loops: From Transcription Byproducts to Threats to Genome Stability.
Molecular Cell 46, 115-124, i: 10.1016 / j.molcel.2012.04.009 (2012). 3 Suraweera, A. et al. Senataxin,
defective in ataxia oculomotor apraxia type 2 is involved in the defense against oxidative DNA damage.
Journal of Cell Biology 6, 969-979 (2007). 4 Bladen, C. L., Udayakumar, D., Takeda, Y. & Dynan, W. S.
Identification of the Polypyrimidine Tract Binding Protein-associated Splicing Factor p54 (nrb) Complex as
a Candidate DNA Double-strand Break Rejoining Factor. Journal of Biological Chemistry 280, 5205-5210,
doi:10.1074/jbc.M412758200 (2005). 5 Li, S. et al. Involvement of p54 (nrb), a PSF partner protein, in
DNA double-strand break repair and radioresistance. Nucleic Acids Research 37, 6746-6753 (2009). 6
Morales, J. C. et al. Kub5-Hera, the human Rtt103 homolog, plays dual functional roles in transcription
termination and DNA repair. Nucleic Acids Research 42, 4996-5006, doi:10.1093/nar/gku160 (2014). 7
Richard, P., Feng, S. & Manley, J. L. A SUMO-dependent interaction between Senataxin and the exosome,
disrupted in the neurodegenerative disease AOA2, targets the exosome to sites of transcription-induced
DNA damage. Genes & Develop-ment 27, 2227-2232, doi:10.1101/gad.224923.113 (2013). 8 Yüce, Ö. &
West, S. C. Senataxin, Defective in the Neurodegenerative Disorder Ataxia with Oculomotor Apraxia 2,
Lies at the Interface of Transcription and the DNA Damage Response. Molecular and Cellular Biology 33,
406-417, doi: 10.1128 / mcb.01195-12 (2013). 9 Richard, P. & Manley, J. L. Transcription termination by
nuclear RNA polymerases. Genes & Development 23, 1247-1269, doi:10.1101/gad.1792809 (2009). 10
West, S., Gromak, N. & Proudfoot, N. J. Human 5--3' exonuclease Xrn2 promotes transcription termination
at co-transcriptional cleavage sites. Nature 432, 522-525 (2004). 11 Wagschal, A. et al. Microprocessor,
Setx, Xrn2, and Rrp6 Co-operate to Induce Premature Termination of Transcription by RNAPII. Cell 150,
1147- 157, doi: http://dx.doi.org/10.1016/j.cell.2012.08.004 (2012). 12 Skourti-Stathaki, K., Proudfoot, N.
J. & Gromak, N. Human Senataxin Resolves RNA/DNA Hybrids Formed at Transcriptional Pause Sites to
Promote Xrn2-Dependent Termination. Molecular Cell 42, 794-805 (2011).
2
1
1
2
(S2503) Senataxin: a new tumor suppressor? Patricia Richard ; Shuang Feng ; Wencheng Li ; Bin Tian ;
1
1
and James L. Manley, Columbia University, New York, NY and Rutgers New Jersey Medical School,
2
Newark, NJ
Senataxin (SETX) is a putative RNA: DNA helicase that is implicated in transcription termination and the
DNA damage response. SETX is known to be mutated in two neurological disorders, AOA2 (Ataxia
Oculomotor Apraxia 2) and a form of Amyotrophic Lateral Sclerosis, ALS4, and has also been found
89 | P a g e
in regulating double strand break repair or the DDR response to transcriptional by-products . In this
study we examine the role of the transcription termination factor Xrn2 in the DNA damage response. Xrn2
is a 5’-3’ ribo-exonuclease involved in several RNA degradation pathways 10-12 . We find that Xrn2 responds
by undergoing nuclear re-localization in response to multiple forms of DNA damage and co-localizes with
transcriptional by-products, in particular RNA:DNA hybrids (R-loops). We find that loss of Xrn2 leads to
increased sensitivity to several forms of DNA damaging lesions and increased genomic instability. Loss of
Xrn2 also leads to increased amounts of replication stress and R-loop formation. We also find that the
nuclear re-localization of Xrn2 is dependent on active transcription and R-loop formation. Loss of Xrn2
also leads to delayed DNA damage repair kinetics in response to ionizing radiation. Importantly, we find
that the difference in DNA repair kinetics in cells that have lost Xrn2 is due to active transcription and
formation of R-loops. This suggest that Xrn2 is involved in regulating transcription after DNA damage and
that this regulation is important for repairing double strand breaks in a timely manner. 1 Kim, N. & Jinks-
Robertson, S. Transcription as a source of genome instability. Nat Rev Genet 13, 204-214 (2012). 2
Aguilera, A. & García-Muse, T. R Loops: From Transcription Byproducts to Threats to Genome Stability.
Molecular Cell 46, 115-124, i: 10.1016 / j.molcel.2012.04.009 (2012). 3 Suraweera, A. et al. Senataxin,
defective in ataxia oculomotor apraxia type 2 is involved in the defense against oxidative DNA damage.
Journal of Cell Biology 6, 969-979 (2007). 4 Bladen, C. L., Udayakumar, D., Takeda, Y. & Dynan, W. S.
Identification of the Polypyrimidine Tract Binding Protein-associated Splicing Factor p54 (nrb) Complex as
a Candidate DNA Double-strand Break Rejoining Factor. Journal of Biological Chemistry 280, 5205-5210,
doi:10.1074/jbc.M412758200 (2005). 5 Li, S. et al. Involvement of p54 (nrb), a PSF partner protein, in
DNA double-strand break repair and radioresistance. Nucleic Acids Research 37, 6746-6753 (2009). 6
Morales, J. C. et al. Kub5-Hera, the human Rtt103 homolog, plays dual functional roles in transcription
termination and DNA repair. Nucleic Acids Research 42, 4996-5006, doi:10.1093/nar/gku160 (2014). 7
Richard, P., Feng, S. & Manley, J. L. A SUMO-dependent interaction between Senataxin and the exosome,
disrupted in the neurodegenerative disease AOA2, targets the exosome to sites of transcription-induced
DNA damage. Genes & Develop-ment 27, 2227-2232, doi:10.1101/gad.224923.113 (2013). 8 Yüce, Ö. &
West, S. C. Senataxin, Defective in the Neurodegenerative Disorder Ataxia with Oculomotor Apraxia 2,
Lies at the Interface of Transcription and the DNA Damage Response. Molecular and Cellular Biology 33,
406-417, doi: 10.1128 / mcb.01195-12 (2013). 9 Richard, P. & Manley, J. L. Transcription termination by
nuclear RNA polymerases. Genes & Development 23, 1247-1269, doi:10.1101/gad.1792809 (2009). 10
West, S., Gromak, N. & Proudfoot, N. J. Human 5--3' exonuclease Xrn2 promotes transcription termination
at co-transcriptional cleavage sites. Nature 432, 522-525 (2004). 11 Wagschal, A. et al. Microprocessor,
Setx, Xrn2, and Rrp6 Co-operate to Induce Premature Termination of Transcription by RNAPII. Cell 150,
1147- 157, doi: http://dx.doi.org/10.1016/j.cell.2012.08.004 (2012). 12 Skourti-Stathaki, K., Proudfoot, N.
J. & Gromak, N. Human Senataxin Resolves RNA/DNA Hybrids Formed at Transcriptional Pause Sites to
Promote Xrn2-Dependent Termination. Molecular Cell 42, 794-805 (2011).
2
1
1
2
(S2503) Senataxin: a new tumor suppressor? Patricia Richard ; Shuang Feng ; Wencheng Li ; Bin Tian ;
1
1
and James L. Manley, Columbia University, New York, NY and Rutgers New Jersey Medical School,
2
Newark, NJ
Senataxin (SETX) is a putative RNA: DNA helicase that is implicated in transcription termination and the
DNA damage response. SETX is known to be mutated in two neurological disorders, AOA2 (Ataxia
Oculomotor Apraxia 2) and a form of Amyotrophic Lateral Sclerosis, ALS4, and has also been found
89 | P a g e
