Why We Worked So Hard to Amplify That Virus
— A Graduate Lab Reflection, March 16, 2015
“Please amplify the adenovirus containing Prox1.”
My professor’s instructions were always short, but they left my mind tangled for days. Why don’t professors ever tell you why they want something done?
Looking back, I think I was his ChatGPT before ChatGPT even existed.
Why Prox1? Why adenovirus? And what on earth was he planning to do with it once I amplified it?These weren’t questions I could ask. As a graduate student, my job was to Google, search papers, and figure it out myself.
In March 2015, in the quiet stillness of a spring lab, I was assigned the task of amplifying a Prox1-expressing adenovirus. At first glance, it seemed like a simple virus propagation job. But as time went on, I found myself contemplating gene destiny, the evolutionary split between blood and lymphatic vessels, and the true identity of a viral vector.
🧬 The Beginning of Lymphatics — and Prox1
The lymphatic system is composed of blind-ended thin-walled capillaries and thicker collecting vessels that return interstitial fluid to the bloodstream. About a century ago, Sabin proposed that endothelial cells sprout from embryonic veins to form primitive lymph sacs, which later give rise to lymphatic networks.
For decades, this idea lacked concrete molecular evidence. That changed with Prox1 knockout mouse studies. These mice failed to develop lymphatic vasculature entirely, leaving only blood vascular structures. When Prox1 was ectopically expressed in human vascular endothelial cells, lymphatic markers increased and blood vessel markers declined.
Thus, Prox1 became known as the “fate-determining factor”—the switch that turns a vascular endothelial cell into a lymphatic one. My task was to amplify this very Prox1 gene using adenovirus, and even today, checking Prox1 expression is still the most direct way to confirm a lymphatic identity. It’s like a cell’s name tag.
🔬 The Virus on the Bench — and the Human Behind It
I didn’t know back then that 293A cells shouldn’t be over-confluent. Or that cytopathic effect (CPE) meant it was time to harvest. I detached cells with trypsin, swirled the plate in a cross pattern, and froze and thawed until the virus was ready.
But all of this required hands-on precision. It took time. I wasn’t a machine—I was a graduate student. A role that, in hindsight, feels incredibly undefined. Neither novice nor master, both worker and thinker.
The goal was simple: to generate enough Prox1 adenovirus for later in vivo studies—hoping to see, finally, the formation of lymphatic vessels.
But to me at the time, it felt overwhelming. As if I wasn’t the one conducting the experiment—the experiment was conducting me.
🔁 Adenovirus, Retrovirus, and the Nature of Expression
Eventually, I found myself wondering: Why adenovirus? Why not retrovirus?
Adenoviruses replicate independently in the cell, like plasmids, enabling fast and transient expression. Retroviruses, on the other hand, integrate into the host genome and sustain long-term expression.
Is speed closer to truth?
Or does enduring expression feel more “real” because it becomes part of the cell?
I know it sounds like a humanities question, but I think science hasn’t fully solved it either. It’s a bit like asking: What came first, the chicken or the egg?
I still don’t have a perfect answer.
But I do know this: experiments always balance on a tightrope between what’s true, and what merely looks like truth.
🌱 Looking Back on the One Who Did the Work
Now, this whole episode could be reduced to a sentence in a paper, maybe even a footnote. But at the time, this felt like the most important task in the world.
In that dark corner of the incubator room, while culturing viruses with tired hands, maybe—just maybe—I was cultivating a fragment of biology’s larger story. With my own hands.
That spring, I was amplifying Prox1.
But I was also amplifying my experiment, my belief, and myself.
March 16, 2015
— From a graduate student’s lab notebook
