Elucidating the Details of the Mechanism,
One by One“homologous recombination”, a conserved error-free DNA repair

Building on this first great achievement, Murayama currently focuses

terms. In the medical context, the SMC5/6 complex is known for its

on a particular event during cell division: DNA replication. He is

deep involvement in viral hepatitis. Thus, in addition to improving ourelucidating the processes that takes place behind the scenes, step byacademic knowledges, understanding the SMC5/6 functions should

step. “What I’ve demonstrated is the fundamental activity of cohesin.

have long-term repercussions for human health.”pathway. “I used to be interested in homologous recombination when
I was a student. The SMC5/6 complex also attracts me in those

I’m still at the start line. Cohesin is considered to serve as a tie forbundling DNA molecules together, but how does it bind to two or
more DNA molecules? Various models have been proposed toanswer this fundamental question, but the mechanism is still
unknown. DNA replication and cohesion establishment areconsidered to proceed in a coordinated manner, so I may need toreconstitute DNA replication concurrently with the attachment ofreplicated sister chromatids. This would be quite an ambitious
project, but if I succeed, I should be able to elucidate the mechanismof chromatid cohesion establishment.”
Because there are so many things we do not understand, it isimportant to focus on these proteins one by one and actually verify
their roles. “It’s really exciting when the proteins actually exhibit theirA Message to Those Interested in Pursuing
Research Careers

designed activities. It’s like building something with Lego blocks.
When I complete one protein, I move on to the next associatedprotein. One by one, I collect components to build a larger system.

Murayama views his own research approach as a “classical andThe ultimate goal is to reconstitute the entire cell.”

textbook approach.” “My research is mainly based on in vitro
reconstitution. This approach is very effective for understanding
molecular mechanisms, but is not really common. Only a few people
are seriously engaged in it. This is because each protein is “unique”
and finding the optimum conditions to induce its activity requires dulland laborious work. Not spectacular at all,” laughs Murayama. “Iadvise the students, don’t get carried away with the trend, go deep
into what interests you. No one else may be interested now, but they
may be later.”
When he started his career at CFR in July 2017, he was impressedby the strong support he received for launching his research. “NIG
offers well-equipped facilities with a lot of equipment and devices
available for shared use.” Murayama also says that “researchersTowards Ultimately Understanding the EntireDynamics of Chromosome Organization

working on the same subject using different approaches give memuch inspiration and motivation. I would like you to spend the bestdays of your lives in the best environment.”

Several types of SMC complexes have been identified; in addition tocohesin, Murayama is also interested in the “third” SMC complex
known as the SMC5/6 complex. “Same as cohesin and condensin,

Interviewer:
Rue Ikeya, Research Organization of Information and Systems

the SMC5/6 complex is an essential protein, it contributes in a
broad-range of chromosome functions including chromosome

Photographer:
Mitsuhiko Kurusu, Office for Research Development

segregation, DNA repair and transcriptional regulation. However, its
function as chromosomal architect is ambiguous, thus this is the mostDecember 2017enigmatic SMC complex. It would be my next challenge.”
Historically, the SMC5/6 complex has been studied as a mutant of2