In the regulation of gene expression in multicellular organisms, I have focused on phenomena characterized by distinctive RNA expression patterns and intracellular distribution, as well as physiological responses mediated by RNAs. I have studied their molecular mechanisms and their roles at cellular and developmental levels. During my research using the nematode C. elegans as a model organism, I have often encountered significant biological phenomena associated with germ cells.
Specially Appointed Senior Assistant Professor TABARA Hiroaki
| Campus | Katahira campus |
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| Laboratory |
Developmental Dynamics
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| Tel | +81-22-217-6195 |
| Website | https://researchmap.jp/HT_genetics |
| Career |
BSc in Biology from the University of Tsukuba; MSc in Biology from the University of Tsukuba; PhD in Genetics from the Graduate University for Advanced Studies (SOKENDAI). Worked as a Postdoctoral Fellow at the University of Massachusetts; a Research Assistant Professor and PRESTO Researcher at Kyoto University; a Postdoctoral Fellow at the University of Tsukuba; a Part-time Lecturer at Tokyo Women’s Medical University; and a Postdoctoral Fellow at the National Institute of Genetics. Currently at Tohoku University since October 2024.
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| Selected Publications |
1. Tabara, H.*, Mitani, S., Mochizuki, M., Kohara, Y., and Nagata, K. (2023). A small RNA system ensures accurate homologous pairing and unpaired silencing of meiotic chromosomes. EMBO J. 42, e105002. *corresponding author
2. Aoki, K., Moriguchi, H., Yoshioka, T., Okawa, K., and Tabara, H.* (2007). In vitro analyses of the production and activity of secondary small interfering RNAs in C. elegans. EMBO J. 26, 5007-5019. *corresponding author
3. Tabara, H., Sarkissian, M., Kelly, W.G., Fleenor, J., Grishok, A., Timmons, L., Fire, A., and Mello, C.C. (1999). The rde-1 gene, RNA interference, and transposon silencing in C. elegans. Cell 99, 123-132.
4. Tabara, H., Hill, R.J., Mello, C.C., Priess, J.R., and Kohara, Y. (1999). pos-1 encodes a cytoplasmic zinc-finger protein essential for germline specification in C. elegans. Development 126, 1-11.
5. Tabara, H., Motohashi, T., and Kohara, Y. (1996). A multi-well version of in situ hybridization on whole mount embryos of Caenorhabditis elegans. Nucleic Acids Res. 24, 2119-2124.
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| Activities in Academic Societies |
A member of the Molecular Biology Society of Japan.
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| Teaching |
Contributed to teaching a Molecular Biology lab course, focusing on molecular genetics of nematodes.
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Recent Activities
Meiosis in eukaryotes is a specialized form of cell division that produces haploid gametes. During meiosis, chromosomes with homologous partners undergo synaptonemal complex (SC)-mediated pairing, while the remaining unpaired regions such as most parts of the sex chromosomes in males are heterochromatinized through unpaired silencing.
I have studied RNA interference (RNAi) using C. elegans as a model organism. RNAi in eukaryotes was initially discovered as a phenomenon in which the introduction of exogenous double-stranded RNA triggers the silencing of genes with homologous sequences. Small RNAs and Argonaute proteins play critical roles in the RNAi mechanism. RNAi-like reactions are also significant in the endogenous regulation of gene expression.
While investigating the RNAi mechanism, I found that mutants lacking the Argonaute protein CSR-1 and its paralog CSR-2, both of which interact with small RNAs, exhibited abnormal meiotic chromosome pairing with severely reduced homology. The lateral elements of the SC are rich in meiotic cohesin. CSR-1 in nuclei and meiotic cohesin were associated with non-simple DNA repeats expressing small RNAs and long non-coding RNAs (lncRNAs) and also associated weakly with protein-coding regions expressing antisense transcripts. The mutants lacking CSR-1 and its paralog also exhibited abnormalities in unpaired silencing of meiotic chromosomes. During meiosis in C. elegans, endogenous RNAi may play an important role in homology recognition, which is required for the accurate pairing of homologous chromosomes as well as the condensation of unpaired chromosomes.
I am working to further understand the biological events associated with meiosis and also developing new experimental techniques to advance my research.
I have studied RNA interference (RNAi) using C. elegans as a model organism. RNAi in eukaryotes was initially discovered as a phenomenon in which the introduction of exogenous double-stranded RNA triggers the silencing of genes with homologous sequences. Small RNAs and Argonaute proteins play critical roles in the RNAi mechanism. RNAi-like reactions are also significant in the endogenous regulation of gene expression.
While investigating the RNAi mechanism, I found that mutants lacking the Argonaute protein CSR-1 and its paralog CSR-2, both of which interact with small RNAs, exhibited abnormal meiotic chromosome pairing with severely reduced homology. The lateral elements of the SC are rich in meiotic cohesin. CSR-1 in nuclei and meiotic cohesin were associated with non-simple DNA repeats expressing small RNAs and long non-coding RNAs (lncRNAs) and also associated weakly with protein-coding regions expressing antisense transcripts. The mutants lacking CSR-1 and its paralog also exhibited abnormalities in unpaired silencing of meiotic chromosomes. During meiosis in C. elegans, endogenous RNAi may play an important role in homology recognition, which is required for the accurate pairing of homologous chromosomes as well as the condensation of unpaired chromosomes.
I am working to further understand the biological events associated with meiosis and also developing new experimental techniques to advance my research.
