Fourteenth Annual Fellows Retreat Recap

The NICHD Fourteenth Annual Meeting of Postdoctoral, Clinical, and Visiting Fellows and Graduate Students took place on April 20, 2018, at the National Museum of the American Indian in Washington, D.C. After a behind the scenes look into the NICHD Office of the Scientific Director by the Scientific Director himself, Dr. Constantine Stratakis, the day kicked off with a keynote by science  policy expert Dr. Yvette Seger. Next, fellows participated in ten round table career discussions (see May issue for a recap), learned insightful career tips from Dr. Ryan Phillip of the Office of Intramural Training and Education, and ended the day with four outstanding fellow research updates and a poster session.

We are excited to bring you the 2018 Annual Fellows Retreat recap, written by our very own NICHD fellows. Enjoy!

Herding Cats for Science: Dr. Yvette Seger’s Career in Policy

By Zelia Worman, PhD

The Keynote address at the 2018 NICHD Fellows Retreat showcased Dr. Yvette Seger, Director of Science Policy at the Federation of American Societies for Experimental Biology (FASEB), who shared with us her eventful journey into science policy and described her day-to-day life. Her talk, entitled “Pipettes to Policy: Transitioning Skills Learned at the Bench into a Career Advocating for Science” focused on how fellows can leverage their laboratory skills to advocate for science. Although Dr. Seger has an impressive biography, she prefers to focus not on her accomplishments, but rather her story.

“At the heart of it all,” as she put it, Dr. Seger came from an Ohio blue-collar family, where voting was engrained in her early on. She was drawn to policy and politics, but also to horses, so she converged her passions by double majoring in Zoology and Politics at Ohio Wesleyan. Eventually “following a boy” to graduate school at Stony Brook University and “falling in love” with the Cold Spring Harbor Laboratory (CSHL), she pursued doctoral training in genetics. While there, she represented CSHL and New York state during Capitol Hill Day. She first realized she was talented at advocating for science when someone asked for her business card, and she didn’t have one!

Passionate about science and policy after her PhD, but not the “nitty-gritty life” of benchwork, she launched her new career at the National Academies of Science, Engineering, and Medicine as a Christine Mirzayan Science and Technology Policy Fellow. Often Dr. Seger talked fondly of her “fairy job mother,” who played a pivotal role in the networking that led to her next positions at FasterCures and Thomson Reuters. Dr. Seger highlighted that she only applied for one job—the rest were obtained through networking.

Describing her current position at FASEB, she compared her daily life to “herding a bunch of cats: scientists, Congress, member societies, agency policies, and the public.” Finding consensus is often challenging, but it is also the most rewarding part of her job. While defining science policy as a constant cycle, she drew the loudest laugh in the room by comparing it to the dreaded KREBS cycle.

Dr. Seger’s main message to fellows was clear: “Paths are going to wander, do not expect a straight line.” She gave advice on how to kick-start a science policy career, naming helpful fellowships as faster paths, but not the sole ones. “Keeping informed on current events, participating in science policy groups, volunteering at a science museum, and contributing articles to newsletters,” she emphasized, are also meaningful experiences. More importantly, Dr. Seger advised fellows to recognize their transferable skills, such as subject matter expertise, analytical thought, and project management. Dr. Seger’s approachable and funny personality, combined with her love for horses, drew everyone’s attention to her concluding wisdom: “Have a plan, but be prepared to change it. Network, make connections, ask questions, and, above all, have fun!”

Retrotransposon Activation: A Genetic Arms Race

By Suna Gulay, PhD

Retrotransposons are ancient genetic elements with the ability to replicate and move to other locations in the genome via RNA intermediates. Their evolution, function and regulation are active areas of research.

Retrotransposons comprise a large fraction of mammalian genomes and can affect gene expression and genomic stability; as such their activation is tightly regulated. In fact, retrotransposons and the transcription factors that regulate them have been found to co-evolve together in what is known as the “arms race model,” preventing potential deleterious effects of retrotransposon activation. One such family of transcription factors is Kruppel-associated box zinc-finger proteins (KRAB-ZFPs), sequence-specific transcriptional repressors in mammals.

Dr. Gernot Wolf, a postdoctoral fellow in Dr. Todd Macfarlan’s lab, has systematically screened the target sequences of more than 100 KRAB-ZFPs by ChIP-sequencing (a way to look at protein-DNA interactions) to define this regulatory effect and to examine the co-evolution of these transcription factors and retrotransposons in mice. He observed that the target sequences map to known retrotransposons, and the deletions of 60 KRAB-ZFP clusters in embryonic stem cells result in retrotransposon activation. Dr. Wolf has constructed mouse models in which these clusters are deleted and observed a positive correlation with transposable element mobilization, indicating the evolution of KRAB-ZFPs specifically to suppress retrotransposons. 

In essence, Dr. Wolf’s work not only supports the evolutionary arms race model for the KRAB-ZFP epigenetic regulators of the mouse, but also has produced models that can be used to study phenotypes associated with retrotransposon reactivation under different environmental conditions.

Scavenger Hunt Inside the Brain!

By Amrita Mandal, PhD

Just like the ozone layer protects us from harmful UV rays, ­­your brain has a protective layer called the meninges. Not only do the meninges protect your brain from external trauma, it also scavenges harmful waste and provides essential nutrients to the brain.

Dr. Marina Venero Galanternik, a postdoctoral fellow in the Weinstein lab, has identified a novel perivascular cell type in the meninges of zebrafish. Due to their morphology, close proximity to blood vessels, and scavenger nature, these cells appear to be a zebrafish equivalent to mammalian Fluorescent Granular Perithelial cells (FGPs). FGPs are brain perivascular cells, found in the cerebral cortex and leptomeningeal layers of the mammalian brain.

Using spectacular live imaging of zebrafish embryos, with molecular and developmental biology techniques, Dr. Galanterik unraveled the origin and function of these little-understood cells. Although the zebrafish FGPs appear to be macrophage-like in morphology, RNA sequencing and single-cell analysis revealed that these cells are more similar to lymphatic endothelium. Lineage tracing analysis has shown these cells transdifferentiate from the optic choroid vascular plexus, which lies deep inside the brain.

Dr. Galanternik’s most recent work has identified a zebrabfish mutant that completely lacks this novel cell type—an important tool to elucidate the function of these cells. She is currently working to characterize these mutants in order to better understand the role and regulation of this novel perivascular cell type in zebrafish. Since many devastating immune and age-related diseases are the result of failed removal of toxic waste, Dr. Galanertik’s work may contribute to future treatment and prevention of related diseases.

The Pretty Important PI—Phosphatidylinositol, That Is

By Kelly Tomins

Phosphatidylinositol (PI) is an important phospholipid with known roles in membrane trafficking, intracellular signaling, and cell metabolism. Differential phosphorylation of this molecule enables it to have distinct regulatory roles and membrane distributions. Surprisingly—given its wide-ranging roles in the cell—researchers have lacked reagents to visualize the localization of precursor PI within the subcellular membranes of intact cells. Dr. Joshua Pemberton, a postdoctoral fellow in the Balla lab, studies the biosynthesis of PI. Since arriving at the NICHD, Dr. Pemberton has created a molecular toolkit of fluorescently-labeled enzymes that allow him to visualize PI within the cell and acutely manipulate PI levels at targeted organelles.

Dr. Pemberton’s project has not been without challenges. To visualize membrane-embedded PI, he fused GFP to a protein known to bind and breakdown PI lipids, but expression of the protein was too toxic for cells. To combat this, Dr. Pemberton created a mutant of the protein that would still bind to PI, but not break it down. The cells survived, allowing him to visualize PI within living cells for the first time. He found that PI is concentrated within the membranes of the Golgi, mitochondria, and peroxisomes. Since the enzyme responsible for the synthesis of PI is anchored within the ER, these new findings indicate special roles for these unique pools of PI lipids in other organelle compartments.

Dr. Pemberton next wanted to create a way to manipulate PI levels at specific target membranes. He turned to his mutant protein again, this time creating a version that maintained catalytic activity, but bound inefficiently to membrane surfaces. Using a chemically-induced proximity system that allows for dimerization of proteins with complementary protein tags (which he placed on distinct membranes and his mutant protein), Dr. Pemberton showed that when PI is hydrolyzed on mitochondrial membranes, the morphology of the mitochondria vastly changes. Overall, these novel molecular tools provide the foundation for exciting new studies that will enhance our understanding of the importance of PI for membrane trafficking and biogenesis.

Molecular Crowdsourcing to Avoid Molecular Crowds

By Adrienne T. Perkins

There are two kinds of people in this world: those who love crowds and those who avoid crowds like the plague. Enter the protein YAP1, a transcriptional regulator involved in cell proliferation and cancer; it hates to be crowded. So when things get cramped in the cytoplasm, how does YAP1 deal? It gets the heck out of there to chill in the nucleus. But just what happens in the cytoplasm to make YAP1 skedaddle, and how does YAP1 get to the nucleus? Dr. Dani Cai, a postdoctoral fellow under the mentorship of Drs. Lippincott-Schwartz and Bonifacino, sought to elucidate the mechanism.

YAP1 is known to be a mechanosensitive protein. When cells flatten on stiff surfaces, YAP1 translocates to the nucleus. Dr. Cai hypothesized that an increase in macromolecular crowding activates the relocation of YAP1. When she decreased cellular volume in live cells with hyperosmotic solution (increasing cellular crowding), she found that GFP-tagged YAP1 formed puncta that localized to the nucleus. Upon washing the cells to increase cellular volume, the puncta disappeared.

As it turned out, YAP1 has liquid-like properties and can coalesce in a liquid phase--this is known as phase separation--and the puncta formed were actually droplets of YAP1. Dr. Cai found that TEAD1, a transcription factor associated with super enhancers, is present in the YAP1 droplets and that the droplets most likely form at super enhancers within the genome. Yet, the YAP1 droplets do not colocalize with markers from other nuclear body droplets, and are therefore unique.

Dr. Cai next showed that deletion of the YAP1 transcription activation domain abolished droplet formation, nuclear localization, and YAP1’s effect as a transcriptional regulator. Collectively, these data represent a novel mechanism for YAP1 and bolster support for phase separation of specific cellular components as more than a parlor trick, but rather a bona fide phenomenon with functional and mechanistic consequences in the cell.

A Quick Recap for Career Success

By Christa Ventresca

"This is it," Dr. Philip Ryan joked as he showed a simple PowerPoint slide, stating that he had 15 minutes for his talk and had to cut it down. Dr. Ryan, Office of Intramural Training and Education (OITE) Deputy Director for Graduate Programs and Student Services, presented the afternoon career talk "Quick Tips for Career Success," a great, short presentation, peppered with personal anecdotes and tips to be successful in science. Dr. Ryan speaks from experience. He holds a bachelor's degree in Biological Sciences and a PhD in Genetics, which he earned through the NIH Graduate Partnership Program and George Washington University.

The talk opened with the simple idea of having a plan. Dr. Ryan emphasized that you should consider your whole self in your plan (scientists tend to take better care of their experimental subjects than themselves). The plan should include clear expectations, strategies for maintaining visibility in your field, career development opportunities, communication practice, and good mentors to help build your professional network.

There are many resources available to fellows at the NIH if you need help forming this plan. Specifically, Dr. Ryan touched on the Workplace Dynamics seminar series, offered through OITE. He commented that this series helped him communicate with his mentor, and he highly recommended it. OITE also offers career counseling; three career counselors are available—each of them are dedicated to the life sciences.

Dr. Ryan focused the bulk of his talk on mentorship. Mentors are people who pass on their knowledge and expertise. They can be anyone within the lab or outside of it, but a great way to find mentors is through networking. Ideally, you will have multiple mentors, to get diverse perspectives and insights into different career paths. Dr. Ryan shared that during his graduate research his mice became sterile. Experienced primarily in genetics, he had to find another mentor to help him gain experience in biochemistry and complete his work.

So how do you select a strong mentor? Dr. Ryan recommended asking four different questions:

1. Does this person have the expertise I need?
2. Can we connect?
3. Is there a good mix of positive feedback and constructive criticism?
4. Will this person make time for me?

At the end of his talk, Dr. Ryan left us with the three things that will never fail you: work hard, work smart, and have fun.