ABSTRACT
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. Maria Sharkova is first author on ‘ Photoreceptor calyceal processes accompany the developing outer segment, adopting a stable length despite a dynamic core’, published in JCS. Maria is a PhD student in the lab of Dr Jennifer Hocking at the Department of Cell Biology, University of Alberta, Edmonton, Canada, investigating the role of microvilli surrounding the sensory ending of vertebrate photoreceptors.
Maria Sharkova
How would you explain the main findings of your paper in lay terms?
Photoreceptor cells in our eyes capture light using massive sensory endings, which are encircled by a ring of finger-like processes. Although we know a lot about the sensory ending itself, we know very little about these processes. We know that they have a core consisting of a structural protein called actin, but beyond that, it is difficult to even label these processes properly in order to learn more about their composition and structure. Our study expands what we know about those structures, from basic parameters to developmental details. We use zebrafish in our experiments, as they have excellent vision, and their retina is organised similarly to that of humans. A key finding is that while the processes maintain a constant length (even when the photoreceptor length changes), the actin core is being continuously recycled. This tells us that the processes are regulated in a precise way, which could be important for understanding how they support vision.
Were there any specific challenges associated with this project? If so, how did you overcome them?
I would say that the initial phase of the project, which involved literature research and project design, was challenging for me. Photoreceptor microvilli (calyceal processes) are absent in nocturnal rodents, and this resulted in limited information being available, given that mice and rats are the most common animal models. Hence, compiling existing knowledge about the processes and identifying research gaps took much longer than anticipated.
When doing the research, did you have a particular result or ‘eureka’ moment that has stuck with you?
I had always thought that Müller glia and the retinal pigment epithelium were physically separated, with each cell type on opposite sides of the photoreceptor layer. I was genuinely surprised when I first observed a large overlap between their apical processes in my images.
Why did you choose Journal of Cell Science for your paper?
I have encountered a lot of JCS papers and found them to be of high quality. Additionally, several people I know have published with The Company of Biologists and recommended JCS to me and my colleagues.
Confocal image of a transverse section through a Tg(sws1:GFP) zebrafish retina, on the level of UV-sensitive cones. GFP, orange; phalloidin-stained actin, cyan. Mitochondria in the photoreceptor inner segment sometimes assume a peculiar shape, as indicated by the absence of GFP signal.
What motivated you to pursue a career in science, and what have been the most interesting moments on the path that led you to where you are now?
I initially began studying medicine; however, I found myself losing motivation when the studies became increasingly clinical. I ended up doing a research internship in the lab of Dr Erez Raz, where I discovered my passion for science. Thanks to the guidance and advice I received from Erez and my former colleagues, I made up my mind and quit my medical studies. I finished a research-oriented BSc and an MSc program shortly after that. Next, I was looking for a place to do an external internship required in my MSc program, and this is how I ended up in Canada. I had a great Skype interview with my current supervisor, Dr Jennifer Hocking. After working on this exciting project for five months, I became really invested in it, so I have returned for PhD studies under Jen's mentorship.
Who are your role models in science? Why?
Two brilliant women who have greatly influenced the scientific community are Alexandra Elbakyan and Elisabeth Bik. Alexandra's Sci-hub project has kickstarted a series of changes within the scientific publishing industry by addressing the lack of accessibility to research papers for disadvantaged researchers and the general population. Elisabeth, with her amazing attention to detail, has highlighted the need for additional mechanisms to protect scientific integrity.
What's next for you?
My next steps are finishing my PhD and applying for a postdoc position.
Tell us something interesting about yourself that wouldn't be on your CV
Two years ago I adopted a cat, and just this week, I started training her. She has already learned to give me a high five when asked! I also have a collection of whiskers she has shed during her time with me.
Maria Sharkova's contact details: Department of Cell Biology, University of Alberta, Edmonton, Canada.
E-mail: [email protected]
