Ben Cox, graduate student in the Ken Poss lab, is sharing his experience at the Society for Developmental Biology’s 77th annual meeting in Portland, OR. Here’s his recap of the third and fourth day. Read his recaps of Day 1 and Day 2 .
Day 3 of SDB featured the session that was likely of greatest interest to scientists in Regeneration Next labs. Lucy O’Brien of Stanford chaired the session titled Development Redux: Stem Cells in Regeneration and Homeostasis, and talked about her lab’s work on Drosophila (fruitfly) intestinal stem cells.
Additional highlights included Karen Liu of King’s College London, who studies bone healing in mammals. The work she presented focused primarily on neural crest-derived frontal bone, which is more osteogenic than parietal or mesodermal osteoblasts and heals faster after postnatal wounding. Her lab is working to identify the basis for this differential healing ability, including the role of Sostdc1 as a dual Wnt/Bmp signaling inhibitor.
Kacy Gordon of Dave Sherwood’s lab at Duke presented work on the C. elegans gonad distal tip cell, which the Sherwood lab uses as a stem cell niche model. She studied the interaction of the distal tip cell and sheath cell Sh1 and found that the interface between the two cells defined a region of germ cell proliferation dependent on actin.
She was followed by Rohan Khadilkar of the University of British Columbia, who studies cell junctions in the lymph gland, a hematopoetic organ, in Drosophila. Through live imaging and RNAi of the extracellular matrix component integrin, his lab showed that the ECM is essential for maintenance of prohemocytes, which will eventually form the hemocytes necessary for immune response to pathogens.
Finally, Regeneration Next director Ken Poss presented work on Vitamin D signaling in cardiomyocyte development, homeostasis, and regeneration. After testing many molecules in a screen using the FUCCI protein system, which consists of fluorescent reporters of cell cycle activation, the Poss lab identified the Vitamin D analog alfacalcidol as a regulator of cardiomyocyte proliferation. Creation of multiple transgenic reporters and signaling mutants confirmed the role of Vitamin D signaling in cardiomyocyte proliferation in all stages of growth and that this effect is dependent on Erbb2 signaling. Further, they showed Vitamin D has broad effects on proliferation and tissue and animal size, not just in cardiomyocytes.
Day 4: The final day was most noteworthy for the award lectures but featured many other talks of interest early in the day. In the Cellular Patterns and Polarity session, Sally Horne-Badovinac from UChicago presented work from her lab, which studies the collective migration of epithelial cells using the Drosophila egg chamber as a model. The egg chamber rotates as it develops as a result of collective migration of follicle cells across the basement membrane. Work from her lab showed that the genes Fat2 and Lar are necessary to specify the leading and trailing edges of these migrating cells. She also showed work on the gene semaphorin-5c, part of a family of genes best known for its role in axon guidance during development. Horne-Badovinac showed that flies with mutations in this gene have a round egg phenotype, and that the gene normally colocalizes with Lar. Her lab has hypothesized that Semaphorin-5c signaling blocks protrusions at the backs of cells, allowing for normal collective migration to occur.
Later, in the Development and the Nucleus session, Rebecca Resnick of Stephen Tapscott’s lab at Fred Hutchison Cancer Research Center investigated the idea of epigenetic memory in development and disease. She showed that the histone variants H3.X and H3.Y, which promote relaxed chromatin and accumulate at the transcription start site of highly expressed genes, are targets of the gene DUX4, a homeobox gene linked to facioscapulohumeral muscular dystrophy. She showed that a burst of this gene during development creates epigenetic memory of the gene expression program through the H3.X and H3.Y histone variants.
The final full session of the conference featured awards lectures. Christian Petersen of Northwestern received the Elizabeth D. Hay New Investigator Award and focused more of his talk on recent and ongoing research compared to the researchers who spoke later, perhaps a result of his relative newness to being an investigator. Petersen works in the planarian Schmidtea mediterranea studying regeneration, and trained under Peter Reddien. This planarian can regenerate its entire body plan after severe injury, and it had previously been shown that inhibition of Wnt signaling was necessary to specify regeneration of the head. Thus, when Wnt signaling is inhibited, regeneration results in the formation of two heads. Several years ago, Petersen showed that the gene Zic-1 is required for anterior pole formation and that its inhibition leads to the formation of two tails. Another gene expressed in the anterior during regeneration, Notum, is downstream of Zic-1 but upstream of Wnt signaling. When Notum is knocked down by RNAi, an uninjured planarian will grow a new pair of eyes while keeping the old. However, only the new pair of eyes can regenerate after acute injury. Studies such as these highlight the role of S. mediterranea in understanding basic tenets of positional control genes and how regeneration can make use of information available via pre-existing tissue.
The other award winners were Robb Krumlauf of Stowers, winner of the Edwin G. Conklin Medal, Eric Wieschaus of Princeton, winner of the Society for Developmental Biology Lifetime Achievement Award, and Drew Noden of Cornell College of Veterinary Medicine, winner of the Viktor Hamburger Outstanding Educator Award. These highly accomplished scientists spoke both on their own work and the history of the field, placing the advances they and their immediate colleagues made into the context of multiple centuries of the study of development. It was a fitting end to a conference that featured a spectrum of research ranging from current undergraduates to a Nobel Prize winner in Dr. Wieschaus.