Please tell us about yourself
Pankaj Dubey is a graduate student in the lab of Dr. Krishanu Ray and the first author of “Localized, Reactive F-Actin Dynamics Prevents Abnormal Somatic Cell Penetration by Mature Spermatids” in this issue. The paper shows how rapid F-actin assembly in the cell enclosing Drosophila spermatids prevents their premature exit.
Where are you from?
I was born in a small village in Uttar Pradesh and grew up in Mumbai. I did my BSc in Biotechnology in Mumbai and then joined the integrated PhD program (Cellular & Molecular Biology) at the Tata Institute of Fundamental Research, Mumbai.
What motivated you to become a scientist?
I always enjoyed reading and learning new things. The earliest curiosity came when I was 8 years old, and my uncle, who is a doctor, asked me what would happen if you keep going up in the sky, and I answered that I would hit the sky! Then I was profoundly surprised when he explained about the emptiness of the sky. I don’t remember when I came to fully accept it, but this incident changed the way I look at things around me. It made me ask questions about many everyday issues. The final push came toward the late stages of my BSc, where reading the brilliantly composed Lehninger’s Principles of Biochemistry by Nelson and Cox attracted me to research.
Is there a particular teacher or mentor who helped guide you on your path?
The mathematics teacher in my school had a huge impact on me. He used to make us solve tough problems on the board and encouraged us to do it fast. We had to think of various possible solutions, test it out in our minds, and then try them on the board. This mental exercise, which I use even today, prepared me for hypothesis building and testing experimental problems.
Do you have a role model in science?
My role models are the late Prof. Obaid Siddiqi and Prof. K. VijayRaghavan. Apart from being brilliant scientists, both were involved in changing the face of biology in India. Prof. Siddiqi started a revolution in biology in India and founded two prestigious institutions in India—the biology unit at Tata Institute of Fundamental Research, Mumbai and National Center for Biological Sciences in Bangalore. Prof. VijayRaghavan, currently the Secretary of the Department of Biotechnology, is working to reduce the bureaucracy in Indian science. His passion is contagious. Both remind us of the greater role of scientists for their community.
What do you tell your friends and family about what you do? Is there something that you would like them to better understand about your research?
I tell them I am working toward the understanding of how cells adhere to each other and how they move. I always get a few chuckles from friends and family when I tell them I am working on how insects release sperm. I would like them to appreciate that biological research is not just about solving diseases. It is more about understating how things work in nature, which eventually leads to the invention of solutions.
Why did you start working on the project?
The first time I discussed this project with my mentor, Prof. Krishanu Ray, he explained it to me in simple terms; he told me we have a cell trapped in a prison made by two other cells and it has to escape it. How does it happen? I immediately fell for this simple and exciting problem.
Did you encounter particular difficulties, and how did you overcome them?
The Drosophila testis is a coiled cylindrical tube, and keeping it alive and localized in one place for long-term imaging was difficult. The testes samples move vigorously in tissue culturing media. Thus, it was unsuitable for long-term live imaging at high magnification. The solution came when we started imaging using phosphate buffered saline instead of the nutrient-rich culture media. Placing a small layer of parafilm on top of the dissected testis sample immobilized it. Using this method, we could monitor morphogenetic movements during late stages of Drosophila spermatogenesis for up to 8 hours. The other problem was a high level of photosensitivity. The addition of the high-sensitive detector (HSD) to the existing Olympus FV1000SPD confocal device reduced the phototoxicity. Altogether, it took me about a year to get the technique right.
Was there a particular result that surprised you?
The abnormal penetration of the somatic head cyst cell by the spermatids upon LatA treatment surprised me. Even in my wildest dream I never thought that the actin cap would be engaged in preventing the penetration by suppressing the enormous push applied by the spermatid bundle. This result completely changed the way we were thinking about spermatid release and role of actin caps, and opened up a whole lot of new questions.
What was the most exciting moment for you? Did you have a “eureka” moment?
The most exciting moment came when we started making movies using the fluorescently labeled F-actin markers and spermatid heads. In the very first movie we made, we saw that long F-actin strands were being formed and dissolved, and we also saw that there were some back-and-forth movements of the spermatid heads. It was 4 in the morning and after more than 100 loops of the movie, it clicked in my head that the F-actin structures were pushing the intruding spermatid heads back. Alone at 4 a.m., staring the laptop screen, I was like “wow, this is beautiful.” This was a “eureka” moment for me. This data explained why we saw abnormal release upon LatA treatment.
How did you celebrate the acceptance of your paper?
I went out with the lab and friends for a few drinks. The celebration went on for a few days.
Is there anyone you think deserves special mention or thanks for your research and paper?
My lab mates and colleagues at DBS deserve special thanks. They have heard my story and every exciting data we had patiently and critically. This really kept my motivation up all throughout my PhD.
In your opinion, what are the most pressing questions for the field?
I think our work just opened up a dormant field. There are many exciting questions including the immediate follow-up of how the intrusion depth is sensed and the molecular machinery involved in sensing the extent of the intrusion. The biggest question that I would say needs to be answered is whether the F-actin dynamics acts as a cellular defense in all eukaryotic cells, or is it specific to head cyst cell.