Tsuneko Okazaki

Tsuneko Okazaki
Born	1933 Nagoya, Aichi Prefecture, Japan
Occupation	Molecular biologist
Years active	1956–present
Known for	Discovery of Okazaki fragments

is a distinguished Japanese molecular biologist best known for her groundbreaking identification of Okazaki fragments alongside her late spouse, Reiji Okazaki. Throughout her scientific career, she has significantly advanced the understanding of DNA replication.

Early life and education

Born in 1933 in Nagoya, Aichi Prefecture, Tsuneko Okazaki completed her secondary education at Aichi Prefectural Asahigaoka Senior High School. She pursued biology at Nagoya University School of Science, where she obtained her doctorate in 1956. That same year, she wed Reiji Okazaki, with whom she maintained a close professional partnership in their research endeavors.

Work leading to and discovery of Okazaki fragments

The Okazakis began their investigations into DNA synthesis and nucleotide properties using frog eggs and sea urchin models, which led to identifying thymidine-diphosphate rhamnose, a nucleotide linked to sugar. This discovery facilitated further research opportunities in the United States at Washington University and Stanford University under the guidance of J. L. Strominger and Arthur Kornberg, where they accessed enhanced resources. Their pivotal 1968 publication in PNAS detailed the discovery of what became known as Okazaki fragments. Following Reiji Okazaki's passing from leukemia caused by Hiroshima radiation exposure in 1975, Tsuneko persevered in their work, validating the RNA primer structure integral to Okazaki fragments.

Additional research contributions

Tsuneko Okazaki has sustained an active role in molecular biology, heading laboratories and mentoring emerging scientists. Her investigations have included the identification of hGCMa as a placenta-specific transcription factor regulating numerous placenta-exclusive genes. She has also contributed to elucidating the function of human centromere protein B in nucleosome positioning on α-satellite DNA sequences. Moreover, her research into HLA-G genomic regulation uncovered a LINE1 element acting as a silencer restricting its expression. Her work further encompasses creating a mouse model for Down syndrome aimed at clarifying genotype-phenotype correlations relevant to human conditions.

Career involvements

Between 1967 and 1983, Tsuneko held an associate professorship in molecular biology at Nagoya University's School of Science before advancing to full professor until 1997. She then joined Fujita Health University's Institute of Comprehensive Medical Science as a professor for five years and continued there as a visiting professor until 2008. From 2004 through 2007, she served as director of the Japan Society for the Promotion of Science's Stockholm office. Later, from 2008 to 2015, she was CEO, president, and director at Chromo Research Inc.

Family life

After returning from research assignments at Washington and Stanford Universities, Tsuneko gave birth to her first child in 1963 and her second in 1973. Managing a demanding full-time scientific career alongside limited childcare options in Japan motivated her active advocacy for enhanced childcare services. Following the death of her husband Reiji in 1975, she continued to advance their shared scientific pursuits.

Recognitions

Tsuneko has been honored with numerous awards including the Chunichi Culture Award and the L'Oréal-UNESCO Award for Women in Science in 2000. That year also saw her receive Japan’s Medal with Purple Ribbon. In 2008, she was bestowed with both the Order of the Sacred Treasure and the Order of the Rising Sun (Gold Rays with Neck Ribbon). To commemorate their contributions, Nagoya University inaugurated the Tsuneko and Reiji Okazaki Award in 2015. That same year, she was designated a Person of Cultural Merit, followed by receiving the prestigious Order of Culture in 2021.

External links

• Comprehensive biography