「様式３－B」

課題番号（Project number） 13

The function of hnRNPR in genome integrity and aging［１］組織（Research group）
代表者（Principal Investigator (PI)）：Zehui Hong
（Medical School of Southeast University, China）
対応者（Host researcher at IDAC）：
Akira Yasui（IDAC, Tohoku University）
研 究 費 (Expenditure report of researchfunds)： consumable goods 300,000 Yen，
［２］研究経過（Research setup）
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are alarge family of proteins, which were first described as a setof proteins binding to mRNA in the cell nucleus. ThehnRNPs are multifunctional proteins involved in manycellular processes such as chromatin remodeling,transcription and telomere elongation (Fig. 1). Recent studies
have shown that hnRNPs are also involved in DNA damage
response and repair. We have identified that 3 hnRNPs(hnRPUL1, hnRNPG, hnRNPR) proteins are recruited toDNA damage sits induced by laser irradiation and these
recruitment are regulated by PARP1.

2.

Analyze the influence of the suppression of eachinteracting protein on genome integrity and cellularaging［３］成果（Research outcomes）（３－１）研究成果（Results）
1. We have determined the response ofGFP-tagged hnRNPR to DNA damage bylaser-micro irradiation (Fig. 2). It accumulated tolaser-irradiated site in Poly(ADP-libose) andPARP1-dependent
manners.
GFP-tagged
hnRNPR accumulated at I-SceI-induced DNA
double-strand break. Therefore, hnRNPR
accumulates at DNA strand breaks whereby
poly(ADP-ribosyl)ation plays an important role.
Fig. 2. Damage response of hnRNPR protein.

Fig. 1 An example of poly(ADP-ribosyl)ation inhnRNP function (Y. Ji and A. V. Tulin, Int. J. Mol.
Sci. 2013).

The function of hnRPUL1 and hnRNPG in DNA damage
response have confirmed by our study and other groups. In
here, we will explore the function of hnRNPR in DNA
damage response, It will help us to understand the functionof hnRNPs proteins in genome stability.
1.

Explore interaction proteins of hnRNPR by affinity
column chromatography performed in IDAC at Prof
Akira Yasui’s lab.

2. Determination of interacting proteins ofhnRNPRThere are a number of hnRNP species within thenucleus, which regulate transcription, We wanted
to determine how hnRNPR interacts with otherproteins and function in response to DNA damage.
hnRNPR was fused behind GST and expressed ininsect cell and purified. Affinity screening of
hnRNPR protein gave rise to the determination of
nuclear proteins possibly interacting with
hnRNPR (Fig. 3). Fig. 3 indicates the presence ofa large complex consisting of various RNA
binding proteins. This complex may be important
for regulation of transcription and translation inresponse to DNA damage.
Fig. 3. Identification of proteins interacting withhnRNPRy mass spectrometry.

50（ ３ － ２ ） 波 及 効 果 と 発 展 性 な ど （ Futureperspectives）
We here characterized hnRNPR by using
laser-micro irradiation and human cell line withmultiple I-SceI sites. hnRNP accumulates at
DNA strand breaks including double-strand
break in a PARP-dependent manner. Since PARP
regulates translation by inhibiting the interactionof hnRNP with mRNA (Fig. 1), PARP-dependentaccumulation of hnRNPR at DNA damage site
may be related to the repression of transcription
at DNA damage site. It will explain a mechanism
ofDNA damage-induced
transcriptionalrepression and DNA repair (transcription-coupledrepair, TCR). Because of the relation n¥between
defective TCR and aging in neural cell, influenceof the hnRNP species on TCR may be quite
important for future aging research.

［４］成果資料（List of Papers）
The results shown in this report is a part of paper
submitted for publication.