In the past week I learned that Robin Reed had passed away.
Robin was a professor in the Cell Biology Department at Harvard Medical School. I first met Robin in 2003 while I was a postdoctoral fellow in Tom Rapoport’s lab. Tom’s lab is on the 6th floor of the Laboratory for Human Reproduction and Reproductive Biology (LHRRB) building at the Longwood Harvard Medical School campus, while Robin’s lab was on the 5th floor. When I arrived in Tom’s lab I was planning to investigate how mRNAs that encode secretory proteins localize to the surface of the endoplasmic reticulum (what we simply called the ER). The ER, just to remind you, is where secretory proteins are made in nucleated cells. Tom’s lab, was THE LAB to be in if you wanted to study the function of the ER.
My plan was to introduce pre-made fluorescent mRNAs directly into cells by microinjection (a technique that I learned in my PhD) and watch them localize to the ER. Although many consider Tom as a cell biologist, he is really a biochemist. His lab had a half-functioning Zeiss microscope that I refused to use, and nothing else. I soon rectified the situation. First up, I needed an injection ‘scope. Fortunately, Tom was good friends with Tim Mitchison, whose lab had a back room full of discarded microscope equipment and parts. I went down to his lab’s back room on the 5th floor, hobbled together a microinjection station, and set it up in an unoccupied room on the 5th floor. Next, I needed a fluorecent microscope to look at the fluorescent mRNA. At first, I used Davie VanVactor’s microscope, then with Tom I wrote an HHMI equipment grant and assembled a nice Nikon microscope imaging station in a dedicated room on the 5th floor.
Soon I established a pipeline, where I made mRNA in a test tube (similar to how they make the mRNA vaccines) and then microinject this into cells. I could thus watch how mRNAs would move around inside the cells at various times. I also worked out a simplified method to stain cells with fluorescent probes that would bind to the microinjected mRNA allowing me to see it. If the fluorophore was incorporated directly into the mRNA it would mess up how the cell translated the mRNA into protein.
The first thing that we noticed is that when I would microinject the mRNA into the cytoplasm, it would aggregate into large structures called stress granules. I did not know this at the time, but many other researchers had previously observed that when in vitro synthesized mRNA was given to animals, it triggered stress responses. Indeed, Kaitlin Kariko and Drew Weissman were at the time working on how to overcome this by substituting uridine for pseudouridine in mNA preparations. I had found that you could overcome this by microinjecting the mRNA into the nucleus. Now the mRNA did not trigger stress, but a further problem appeared, the mRNA had to be exported from the nucleus to the cytoplasm before it could make it to the surface of the ER. And this is where I had my “Hmm, that’s interesting” moment. Depending on the composition of the mRNA, it would sometimes be exported, and sometimes not. Why was this?
Fortunately for me, Robin Reed, one of the world experts on mRNA nuclear export was right downstairs from Tom’s lab, literally around the corner from my microscope room. Soon I started attending the Reed lab meetings and became friends with some of her postdocs including Anusha Dias and Brian Lee. I learned a lot about the field, about the main ideas. Annusha and I started working together and I taught her microinjection and how to stain for the injected mRNA.
I had made several discoveries. I would share these with members of the Reed lab. But some of what I found contradicted Robin’s view of how mRNA nuclear export worked. Not that Robin was wrong, but that reality was a bit more complicated than her models suggested.
I eventually published my work. I had found that certain elements in an mRNA would promote its export. I also showed that if the mRNA lacked these elements, but was spliced, then it would also be exported. The first finding was an anathema to Robin, the second finding validated her previous publications. Both Anusha and Brian are coauthors on that paper. But Robin refused to be on the paper. She let us know that she could not be associated with it in any way. We still thanked her in the acknowledgement section, against her wishes. This paper and this work really dictated the rest of my career. Why are certain mRNAs exported? Why are others not exported? What were the rules? What was the point of this?
This work was truly the launching pad to my own scientific journey. This was not what I was trained to do. This is not what Tom had in mind. This journey led me down the path to thinking about how genes evolve. Into why we had a nucleus. Into the nuts and bolts of how evolution actually worked. It was my own scientific journey, untethered to anything that my mentors had done.
Without Robin’s help I would have never taken this path. So although our relationship soured, I do owe my scientific journey, in part, to her.