Kanazawa University, Graduate School of Medicine, traces its roots from Hikoso Vaccination Center established in 1862. Later, in 1912, a medical chemistry laboratory was established at the Kanazawa Professional School of Medicine to educate medical students, which was the foundation of this laboratory. Dr. M. Muramatsu joined this laboratory as the 6th Professor in 2007. Previously, he studied the molecular mechanism underlying immunoglobulin gene diversification at Kyoto University (under Prof. Honjo’s supervision). In 1999, he isolated a novel gene, activation-induced cytidine deaminase (AID), and proved that it was essential for immunoglobulin class switch recombination and somatic hypermutation.
Elucidation of the molecular function of AID is one of the major research projects of this laboratory. Our research interests also include the other proteins of its family, that is, the APOBEC deaminase family. The APOBEC family consists of a group of proteins that convert cytosine residues to uracil in DNA and/or RNA, and consists of 11 members: AID, APOBEC1, APOBEC2, APOBEC3A, APOBEC3B, APOBEC3C, APOBEC3DE, APOBEC3F, APOBEC3G, APOBEC3H, and APOBEC4. Our current focus is on the elucidation of the pathophysiological role of AID/APOBEC deaminases in viral infection and oncogenesis.
Our laboratory is also actively engaged in the education of medical students, especially with regard to biochemistry and molecular biology. To encourage medical students, we provide them an opportunity to learn more about basic sciences.
Needless to say, English is the medium of instruction for various research activities, such as research meetings, seminars, and training of students in our laboratory. Knowledge and skill of the Japanese language is not a pre-requisite to join us. If you are interested in our projects or wish to be a master/PhD course student, please send us an E-mail. Students are also welcome to join us for pursuing short-term research projects (as a research student).
by Masamichi Muramatsu
|Associate Professor||:||ENAMI, Masayoshi|
|Assistant Professor||:||KITAMURA, Kouichi|
|Assistant Professor||:||WAKAE, Kousho|
|Technical staff||:||KOURA, Miki|
|Technical staff||:||SHIMAZU, Miyuki|
In early 2000, a series of studies showed that the human genome contains more than 10 DNA/RNA cytidine deaminases; these are now known as APOBEC family proteins (fig. 1). APOBEC was named after a founder gene, APOBEC1 (ApoB100 editing catalytic subunit 1). The human genome contains at least 11 APOBEC proteins. All APOBEC proteins have one or two cytidine deaminase active site motifs that contain a single Zn finger. APOBEC1 is an RNA editing protein that is responsible for apolipoprotein B100 RNA editing. APOBEC3 is a DNA deaminase responsible for C to U conversion in the viral genomic DNA and in retrotransposons. Since APOBEC enzyme activity results in obvious accumulation of C to T and G to A mutations in the viral genome, this mutation accumulation is called as hypermutation. Interestingly, in humans, APOBEC3 diversifies into 7 subfamilies (A3A~A3H) and is clustered on chromosome 22 as a gene cluster, while rodents have only a single APOBEC3. In addition, some human immunodeficiency virus-1 (HIV-1) substrains evolve viral infectivity factor (VIF), which can inactivate APOBEC3 along with the viral genome, suggesting a strong evolutionary linkage between APOBEC3 diversification and HIV-1 survival. Recent high-throughput whole-genome sequencing of the cancer genome has detected kataegis mutation (phenomenon that accumulate C-to-T and G-to-A mutations within a small portion of the genome), suggesting the role of APOBEC3 in the progression of the cancer genome.
Example of APOBEC participation in the host-virus relationship rapidly increases in the last 10 years. We believe that APOBEC/AID deaminases are extremely important players for understanding virus infection, innate immunity, autoimmune diseases, virus-driven carcinoma, and the host-pathogen relationship. Using molecular biological approaches, we wish to determine the relationship between the host and virus; APOBEC/AID proteins are a good example of host proteins that can be used for this purpose.
Currently, using in vitro models of human hepatitis B virus (HBV) and papillomavirus (both of which widely known to cause human cancers), we have been trying to answer following questions:
- How do the host factors suppress virus replication?.
- How does a virus counteract host antiviral activities?
- How does a viral infection lead to tumorigenesis?
- Are the host antiviral factors involved in virus-related tumorigenesis?
- Are there any host factors that determine the individual susceptibility to virus infection and tumorigenesis?
- Do APOBEC proteins generate drug resistant viruses?
Regarding influenza viruses, we have projects as follows:
- Development and clinical evaluation of Reverse Genetic (RG) vaccine against highly pathogenic avian influenza (HPAI), in collaboration with Bogor University, and Airlangga University Tropical Disease Centre in Indonesia.
- Molecular basis of cellular response and pathogenicity during influenza virus infection.
We always welcome graduate students with much enthusiasm.
Japanese government and JSPS have some system to support foreign students in Japan. To get more information, please also visit their official sites.
- http://www.studyjapan.go.jp/en/index.html [Ministry of Foreign Affairs of Japan]
- http://www.jsps.go.jp/english/e-fellow/index.html [Japan Society for the Promotion of Science]
- http://www.adm.kanazawa-u.ac.jp/ie/e/index.html [Scholar ship information from Kanazawa University]
Kanazawa University Graduate School of Medical Science
13-1 Takara-machi, Kanazawa 920-8640, Japan.
Mail: M. Muramatsu or our office
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