We are so proud to share that our “pandemic paper,” “Septins and a formin have distinct functions in anaphase chiral cortical rotation in the C. elegans zygote,” has been accepted for publication in Molecular Biology of the Cell, the journal of the American Society for Cell Biology.
Former Honors Thesis student Adhham Zaatri started as a work-study worker, then learned cell biology, and drove this project for much of his undergrad studies. After he graduated, he worked over the internet with postdoc Jenna Perry to finalize and submit the manuscript. Once regaining access to the lab, and while juggling several other projects, Jenna earned co-first-authorship by completing several referee-suggested experiments that truly advanced our thinking on the topic and strengthened the story.
The science, you ask? We studied the cortical dynamics of the C. elegans zygote in cytokinesis, and noticed that in addition to contractile ring formation and constriction, the cortex also flows around the circumference of the cell, with consistent handedness (see curl of fingers in schematic). When we started this work over a decade ago, we knew that the handedness of the rotation was the opposite of that observed by colleagues in Germany. By imaging a printed letter “F” on our microscope, Jenna determined that Olympus and Nikon scopes display objects with mirrored handedness, with respect to the naked eye. (Zeiss and Leica scopes preserve real-world chirality.)
For our paper, we used particle image velocimetry to quantify rotation, and then report that septins are required for rotation. Thinking that this may be due to an effect on F-actin filaments generated by the formin CYK-1, we explored its localization and found that it is enriched in the zygote posterior in a septin-dependent manner. This suggested that this pole of the cell is analogous to the dorsal side of cultured mammalian cells, which the Bershadsky group showed tilt their initially-radial F-actin bundles. We went on to show that CYK-1 is not required for cortical rotation, but is essential for the direction and persistence of rotation. We conclude that anaphase cortical rotation results when chiral torsional stress accumulated in the cortical network via actin polymerization from membrane-anchored formins is relieved by cytokinetic ring contractility. The septins could play one or more roles in network connectivity (see green hypotheses in schematic).
Amy was thrilled to receive official news that she has been promoted to Full Professor of Biology at UNC. She thanks her lab members for their amazing work, the many US and Canadian funding agencies that have supported them, her department for their support and advocacy, and all her mentors throughout the years.
We mourned the lost opportunity to connect with former MDX lab members, which we normally do at the annual meeting of the American Society for Cell Biology. But we saw even more people than we would have that way, by holding a reunion on Gather! It was fun to introduce new and old members, catch up on what people are doing now, and meet the babies!
At ASCB itself, Jenna, Michael, and Jack presented posters, and Daniel presented an invited talk (for the 4th year in a row!).
Covid silver lining: we can readily share our enthusiasm for research via zoom and Google classrooms! Amy connected with K-12 students via Skype-a-Scientist, and presented a seminar at a nearby HBCU, NC A&T. Both audiences had abundant thoughtful questions! Amy was enriched by the opportunity to connect.
Amy enjoyed seeing smiling faces and names from our big, diverse department and from as far away as Montreal. The zoom meeting approximated a packed lecture hall and was a celebration of past and ongoing work by all members of the lab.
Have you ever wondered how the chirality of minuscule cellular components is manifest at the cell- or organism level? Adhham and Jenna found that the septins are required for the cortical rotation that occurs with consistent handedness, in early anaphase in the C. elegans zygote. While the septins are required for rotation to occur at all, the formin CYK-1 is required for the consistency of handedness and persistence of cortical flow. Check it out on BioRxiv and look out for it in a favorite journal soon!
Daniel’s work modeling non-muscle contractility and cell division in the C. elegans zygote and in silico using particle-based simulations was recognized with a position on an NIH training grant awarded to UNC’s Lineberger Comprehensive Cancer Center. We are all proud of and grateful for this honor.
Coleman started in the lab several years ago, via the Federal Work Study program, and quickly made key contributions to ongoing work on contractile oscillations. He applied lessons from coursework in Statistics and Operations Research and taught us all a lot. The summer before his senior year he was awarded a prestigious SURF summer research fellowship to work full time in the lab. During that time, he learned the entire experimental workflow, culturing worms, dissecting zygotes, and acquiring image data on the confocal. He worked in the lab briefly after graduating, and recently moved to the University of Wisconsin at Madison for graduate studies in Biostatistics. We miss him and wish him well!
Larry worked in the lab for several years as an undergraduate, and then completed his Honors Thesis on septins in cytokinesis and the effects of septin alleles on multimerization. He was a tech for one year, and was accepted to med school. Here he is after getting his white coat!
With NIH/NHLBI’s Clare Waterman and UNC’s Amy Gladfelter, Amy co-organized a Nikon-sponsored Cytoskeleton seminar series for the Marine Biological Labs’ MBL Virtual Programming in July. On three consecutive Tuesday evenings, we enjoyed excellent talks and massive, global turn-outs to hear our speakers: Princeton’s Sabine Petry, NIH’s Jadranka Loncarek, and MIT’s Lindsay Case. Lively Q&As followed. And each session began with the most charming, heartstring-pulling video walk-through of the MBL, for all of us missing this scientific homeland. Check it out!