Page 120 - 2014 Printable Abstract Book
P. 120
repair gene defects, including Fanconi anemia. The mechanism of this effect and the potential
involvement of other organs are currently under investigation.
(PS1-31) Transcriptome analysis of radiation-responsive genes in Cryptococcus neoformans. Dongho
2
1
1
1
Kim, Ph. D. ; Choi Jaehyuk ; Minho Joe ; Sangyong Lim ; and Yong-Sun Bahn, 3 Department of
1
Biotechnology, Korea atomic energy research institute, Jeongeup-si, Jeollabuk-do, Korea, Republic of ;
Division of Life Sciences, College of Life Sciences and Bioengineering, Incheon National University,
2
Incheon, Korea, Republic of ; and Department of Biotechnology, Center for Fungal Pathogenesis, College
3
of Life Science and Biotechnology, Yonsei University, Seoul, Korea, Republic of
The basidiomycete fungus Cryptococcus neoformans is a yeast-form eukaryote, majorly known as
a human pathogen in immunocompromised individuals. This fungus exhibits much greater resistance to
γ-irradiation than baker’s yeast, Saccharomyces cerevisiae. Here, we identified genes involved in radiation
response and adaptation and elucidated a unique regulatory system for radiation-resistance in C.
neoformans. The fungal cells were exposed to 3 kGy of γ-irradiation for 1 h and then incubated for 30, 60,
and 120 m for recovery. The DNA microarray-based transcriptome analysis revealed that 294 and 627
genes were up- and down-regulated, respectively. Based on gene ontology data, the genes involved in
chromosome stability, DNA damage repair system, and protein modification were highly induced,
suggesting that damaged DNA and proteins stimulate cellular recovery and recycles. In contrast, genes
involved in biosynthesis of nucleobases, amino acids, and fatty acids, nuclear migration, and pathogenesis
were significantly down-regulated in response to γ-irradiation. It suggest that emergent recovery in the
cells may be shutting down general catabolic pathways for cellular growth. Taken together, these results
can make a contribution to explore genetic pathways in the radiation-resistant C. neoformans.
(PS1-32) Rad9 regulates the base excision repair gene Neil1. Sunil K. Panigrahi, Ph.D, Center for
Radiological Research, New York, NY
RAD9 is well known for its role in DNA damage induced cell cycle checkpoint control and DNA
repair. As a member of the RAD9-RAD1-HUS1 (9-1-1) heterotrimeric complex, it acts as a sensor of DNA
damage that enables ATR kinase, independently recruited to the site of damage, to activate downstream
effectors. RAD9 is known to physically interact with the NEIL1 DNA glycosylase, an ortholog of bacterial
Nei/Fpg involved in removal of oxidatively damaged DNA bases as part of the base excision repair (BER)
pathway. In addition, RAD9 binds to various other DNA repair proteins and, in most cases, such
interactions alter the function of the target protein and downstream signaling. Moreover, it has been
shown that RAD9 can act independently of the 9-1-1 complex as a transcription factor to regulate a
number of genes including p21 Waf1/Cip1. In this study, we show that mouse ES cells null for mRad9 have a
+/+
reduced level of Neil1 protein relative to Rad9 cells. We also found a reduced level of NEIL1 in human
prostate cancer cell line knocked down for RAD9 by RNA interference. Herein, we provide evidence that
Rad9 is required for Neil1 protein stability in mouse ES cells, whereas it regulates NEIL1 expression at the
transcriptional level by promoter binding in human prostate cancer cells. In both cases RAD9 depleted
cells are more sensitive to oxidative stress as compared to the wild type counterpart. In BER assay using
a 24mer substrate, we found that Glycosyalse/Apurinic lyase activity (incision) was reduced in mouse ES
cells null for Rad9. The incision activity was restored by ectopic expression of either Neil1 or Rad9 to the
118 | P a g e
involvement of other organs are currently under investigation.
(PS1-31) Transcriptome analysis of radiation-responsive genes in Cryptococcus neoformans. Dongho
2
1
1
1
Kim, Ph. D. ; Choi Jaehyuk ; Minho Joe ; Sangyong Lim ; and Yong-Sun Bahn, 3 Department of
1
Biotechnology, Korea atomic energy research institute, Jeongeup-si, Jeollabuk-do, Korea, Republic of ;
Division of Life Sciences, College of Life Sciences and Bioengineering, Incheon National University,
2
Incheon, Korea, Republic of ; and Department of Biotechnology, Center for Fungal Pathogenesis, College
3
of Life Science and Biotechnology, Yonsei University, Seoul, Korea, Republic of
The basidiomycete fungus Cryptococcus neoformans is a yeast-form eukaryote, majorly known as
a human pathogen in immunocompromised individuals. This fungus exhibits much greater resistance to
γ-irradiation than baker’s yeast, Saccharomyces cerevisiae. Here, we identified genes involved in radiation
response and adaptation and elucidated a unique regulatory system for radiation-resistance in C.
neoformans. The fungal cells were exposed to 3 kGy of γ-irradiation for 1 h and then incubated for 30, 60,
and 120 m for recovery. The DNA microarray-based transcriptome analysis revealed that 294 and 627
genes were up- and down-regulated, respectively. Based on gene ontology data, the genes involved in
chromosome stability, DNA damage repair system, and protein modification were highly induced,
suggesting that damaged DNA and proteins stimulate cellular recovery and recycles. In contrast, genes
involved in biosynthesis of nucleobases, amino acids, and fatty acids, nuclear migration, and pathogenesis
were significantly down-regulated in response to γ-irradiation. It suggest that emergent recovery in the
cells may be shutting down general catabolic pathways for cellular growth. Taken together, these results
can make a contribution to explore genetic pathways in the radiation-resistant C. neoformans.
(PS1-32) Rad9 regulates the base excision repair gene Neil1. Sunil K. Panigrahi, Ph.D, Center for
Radiological Research, New York, NY
RAD9 is well known for its role in DNA damage induced cell cycle checkpoint control and DNA
repair. As a member of the RAD9-RAD1-HUS1 (9-1-1) heterotrimeric complex, it acts as a sensor of DNA
damage that enables ATR kinase, independently recruited to the site of damage, to activate downstream
effectors. RAD9 is known to physically interact with the NEIL1 DNA glycosylase, an ortholog of bacterial
Nei/Fpg involved in removal of oxidatively damaged DNA bases as part of the base excision repair (BER)
pathway. In addition, RAD9 binds to various other DNA repair proteins and, in most cases, such
interactions alter the function of the target protein and downstream signaling. Moreover, it has been
shown that RAD9 can act independently of the 9-1-1 complex as a transcription factor to regulate a
number of genes including p21 Waf1/Cip1. In this study, we show that mouse ES cells null for mRad9 have a
+/+
reduced level of Neil1 protein relative to Rad9 cells. We also found a reduced level of NEIL1 in human
prostate cancer cell line knocked down for RAD9 by RNA interference. Herein, we provide evidence that
Rad9 is required for Neil1 protein stability in mouse ES cells, whereas it regulates NEIL1 expression at the
transcriptional level by promoter binding in human prostate cancer cells. In both cases RAD9 depleted
cells are more sensitive to oxidative stress as compared to the wild type counterpart. In BER assay using
a 24mer substrate, we found that Glycosyalse/Apurinic lyase activity (incision) was reduced in mouse ES
cells null for Rad9. The incision activity was restored by ectopic expression of either Neil1 or Rad9 to the
118 | P a g e
