First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Roshan Lal Shrestha is first author on ‘ The histone H3/H4 chaperone CHAF1B prevents the mislocalization of CENP-A for chromosomal stability’, published in JCS. Roshan Lal is a research fellow in the lab of Dr Munira A. Basrai at the National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD, USA, investigating the mechanisms of chromosomal instability and aneuploidy.

Roshan Lal Shrestha

How would you explain the main findings of your paper in lay terms?

A cell is the basic unit of life. In the human body, there are trillions of cells that divide continuously. When a cell divides, 23 pairs of chromosomes must separate into each daughter cell precisely. Failure results in cancers and genetic or developmental disorders. Among the proteins that play vital roles in cell division is a protein called CENP-A, which must localize at a specialized area in a chromosome called the centromere. However, several studies, including ours, have shown that when CENP-A mislocalizes to regions other than the centromere, it results in an unequal distribution of chromosomes into each daughter cell. This is known as chromosomal instability (CIN), which is one of the predisposing factors for developing cancer. Therefore, it is important to understand what causes the mislocalization of CENP-A, so that we can prevent CIN. In this study, we examined about 500 proteins and identified a protein called CHAF1B that ensures that CENP-A localizes at the centromere and not to other places, preventing CIN.

Were there any specific challenges associated with this project? If so, how did you overcome them?

From our previous findings we knew that the mislocalization of CENP-A is not a favorable condition for a cell. So, it was important to understand which proteins or pathways play roles in preventing CENP-A mislocalization. However, there are thousands of proteins in a cell, and identifying a protein or a set of proteins that prevent(s) CENP-A mislocalization was a big challenge. But, thanks to the development of a technique called high-throughput RNAi, which blocks the synthesis of hundreds of proteins one at a time, we were able to pinpoint a few proteins and pathways that prevent the mislocalization of CENP-A. We generated a cell line that expresses YFP-tagged CENP-A so that we could visualize CENP-A under the microscope. Furthermore, we optimized the protocol to examine single chromosomes in a cell so that we could precisely locate CENP-A on the chromosome.

When doing the research, did you have a particular result or ‘eureka’ moment that has stuck with you?

When I started my PhD in the Department of Genetics, University of Cambridge, UK, under the supervision of Dr Viji Draviam back in 2011, I became fascinated watching chromosomes in dividing cells moving towards two daughter cells using time-lapse microscopy. It was a moment of pride for me to be one of a few among billions on the earth who could visualize this process. I grew more interested in this cellular event when I could see how cells fail to divide properly upon a certain genetic perturbation. Since then, I have been involved in this aspect of biomedical research to identify novel pathways that prevent erroneous cell division, hoping to understand cancer development in greater detail.

Why did you choose Journal of Cell Science for your paper?

I utilized several cell biology and microscopy techniques in this study, and I believe that Journal of Cell Science has many readers with great interest in research studies related to crucial cellular events.

Chromosomes immunostained with CENP-A showing mislocalization of CENP-A to non-centromeric regions in cells depleted of CHAF1B. Scale bars: 5 μm.

Chromosomes immunostained with CENP-A showing mislocalization of CENP-A to non-centromeric regions in cells depleted of CHAF1B. Scale bars: 5 μm.

Have you had any significant mentors who have helped you beyond supervision in the lab? How was their guidance special?

I joined Dr Viji Draviam's laboratory, where I gained experience in the field of cell division. Prior to that, I had only basic knowledge about cell division, as my undergraduate degree was in medical laboratory science. It was Dr Draviam's support that has helped to hone my academic and technical skills and publish papers in good journals. Currently, I am working with Dr Munira Basrai at NCI/NIH, who is equally supportive and never misses any opportunity to expose me to the scientific community, which I believe is very important to move forward in my career.

What motivated you to pursue a career in science?

Science allows you to come closer to something that you never realized existed before as it helps to actually see the molecular processes we think about. I am always amazed by the enthusiasm and curiosity that scientists have when they talk about science. These are the factors that are still driving and motivating me to pursue a scientific career.

What's next for you?

My career goal is to lead my own research lab and explore more research on aneuploid tumors.

Tell us something interesting about yourself that wouldn't be on your CV

I like creating digital event/travel vlogs and informative short movies. I enjoy editing videos and writing scripts in my free time. It helps me to refresh my mind.

Do you have any suggestions for graduate students?

You should love science and be curious and enthusiastic. Do not do science just to get an academic degree, but do it to make an impact.

Roshan Lal Shrestha's contact details: National Cancer Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA.

E-mail: roshan.shrestha@nih.gov

Shrestha
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R. L.
,
Balachandra
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V.
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Kim
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J. H.
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Rossi
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A.
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Vadlamani
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Ozbun
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L.
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Lin
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S.
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Cheng
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K. C.-C.
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Chari
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R.
et al. 
(
2023
).
The histone H3/H4 chaperone CHAF1B prevents the mislocalization of CENP-A for chromosomal stability
.
J. Cell Sci.
136
,
jcs260944
.