This month, we’re highlighting a trainee in a QB3-Berkeley lab by speaking with Marco Dueñas, who is a plant biology PhD candidate in Sabeeha Merchant’s lab. His research focuses on using green algae as a platform for fundamental discovery and synthetic biology.
QB3-Berkeley: What inspired you to pursue research in this field and to join Sabeeha Merchant’s lab?
Marco Dueñas: Growing up, my mom and dad loved a clean house, so I was only allowed fish as pets, sparking my love of aquatic biology and science in general. When it was time for college, I attended UC Riverside, which lacks an ocean but has extensive farmland surrounding it, so I studied and gained an appreciation for plant biology.
For grad school, studying algae became the perfect way to merge my interests in aquatic systems and plant science. Sabeeha Merchant at QB3-Berkeley is a world-renowned scientist and pioneer of algal research, so when she offered me a position in her lab, I was thrilled!
QB3: Can you summarize your recent paper in a way that a non-expert would understand?
MD: Eukaryotic mRNAs are traditionally thought to translate only one protein per transcript due to ribosome initiation mechanisms. Challenging this view, the Merchant lab discovered hundreds of conserved “polycistrons” in green algae, where a single mRNA produces multiple proteins, though the mechanism was unknown.
In our paper published in PNAS earlier this year, we show that this occurs through leaky scanning, where the ribosome sometimes bypasses the first translation start site and initiates translation at a downstream site. This finding not only provides a tool for precise protein expression, but also evidence that similar polycistrons exist across eukaryotic genomes with important metabolic functions.
QB3: What advice would you give to other grad students preparing to publish their first paper?
MD: Every PhD project has its challenges but publishing your first paper is especially tough. I first struggled with experiments, then found the writing process even harder, and finally realized that getting it published in a journal is its own battle.
Mentorship is everything: Sabeeha and co-corresponding author Jeffrey Moseley really taught me all the work and thought that goes into a paper. Remember to stay humble, be open to criticism, celebrate the wins, and learn from the losses—eventually, everything will come together.
QB3: What challenges did you face while working on this project, and how did you overcome them?
MD: When I started this project, I approached it with an engineering mindset, asking, “How can I apply this?” In reality, we still didn’t understand the mechanism, leaving me stuck in a cycle of failures.
After stepping back and reading the literature, I realized this wasn’t just about making a tool but rather a fundamental study of translation. I never intended to study the specifics of protein translation during my PhD, but it was really rewarding to become knowledgeable in that field and see the project finally come together.
QB3: What’s your go-to way to celebrate a research milestone?
MD: In the rush to reach milestones, it’s easy to take for granted the memories and the people who kept you going, so I like to take a moment to stop and reflect. The 3 a.m. calls with my brother to pass the time while I run a gel; the nerves before my first big research talk melting away as I spot my wife smiling front and center in the audience; my mom’s eyes lighting up when she calls her son a “scientist,” and sitting with my dad during his chemo treatments, watching The Lord of the Rings for the millionth time while we chat about my next big idea. I wouldn’t trade those moments for the world.