{"65119":{"#nid":"65119","#data":{"type":"news","title":"Bird Embryo Provides Unique Insights into Developmental Phenomena","body":[{"value":"\u003Cp\u003EAvian embryos could join the list of model organisms used to study a specific type of cell migration called epiboly, thanks to the results of a study published this month in the journal \u003Cem\u003EDevelopmental Dynamics\u003C\/em\u003E. The new study provides insights into the mechanisms of epiboly, a developmental process involving mass movement of cells as a sheet, which is linked with medical conditions that include wound healing and cancer.\u003C\/p\u003E\n\u003Cp\u003EThe study, published online on March 15, explains how epithelial cells expand as a sheet and migrate to engulf the entire avian egg yolk as it grows. It also reveals the presence of certain molecules during this process that have not been previously reported in other major developmental models, including Xenopus frogs and zebrafish.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022These molecules and mechanisms of early development in the avian embryo may demonstrate evolutionary differences across species in the collective movement of epithelial cells and motivate additional studies of avian embryo development,\u0022 said Evan Zamir, an assistant professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech.\n\u003C\/p\u003E\n\u003Cp\u003EMatt Futterman, who worked on the project as a graduate student at Georgia Tech, and mechanical engineering professor Andr\u00e9s Garc\u00eda also contributed to this study. The research was funded by Zamir\u0027s new faculty support from Georgia Tech and by a grant to Garc\u00eda from the National Institutes of Health.\n\u003C\/p\u003E\n\u003Cp\u003EIn the study, the researchers conducted immunofluorescence and high-resolution confocal microscopy experiments to examine the spatial distribution and expression of five proteins -- vimentin, cytokeratin, \u03b2-catenin, E-cadherin and laminin -- as cells moved to wrap the yolk sac of quail embryos during development.\n\u003C\/p\u003E\n\u003Cp\u003EThe results showed that during this process, four of the proteins -- vimentin, cytokeratin, \u03b2-catenin and E-cadherin -- appeared in the cells located at the free edge of the migrating cell sheet. Finding dense interconnected networks of both vimentin and cytokeratin in the edge cells surprised the researchers.\u003C\/p\u003E\n\u003Cp\u003E\u0022Since cytokeratin is generally associated with the epithelial phenotype and vimentin is generally associated with the mesenchymal phenotype, it\u0027s rare to see them expressed in the same cells, but this does occur in metastasizing tumor cells,\u0022 said Zamir.\n\u003C\/p\u003E\n\u003Cp\u003ECells expressing the mesenchymal phenotype are typically found in connective tissues -- such as bone, cartilage, and the lymphatic and circulatory systems -- whereas cells of the epithelial phenotype are found in cavities and glands and on surfaces throughout the body.\n\u003C\/p\u003E\n\u003Cp\u003EThis finding provides evidence that epithelial cells normally attached to a membrane surface underwent biochemical changes that enabled them to assume a mesenchymal cell phenotype, which enhanced their migratory capacity. This process, called partial epithelial-to-mesenchymal transition, has many similarities to the initiation of tumor cell metastasis and wound healing.\n\u003C\/p\u003E\n\u003Cp\u003ESince this epithelial and mesenchymal expression pattern in the edge cells has not previously been reported in Xenopus or zebrafish, it may be unique to the avian embryo. This discovery would make the avian embryo a valuable model for studying tumor cell migration and wound healing.\n\u003C\/p\u003E\n\u003Cp\u003EIn addition to detailing protein expression in the quail embryo during development, the researchers also determined the origin of the new cells required at the migrating edge to cover the growing yolk. During development, the radius of the quail yolk doubles every day for the first few days, representing a hundreds-fold increase in the egg yolk surface area. \u003C\/p\u003E\n\u003Cp\u003E\u0022For each individual cell that has to cover the egg yolk as it grows, the migration around the yolk is extraordinary, because it\u0027s such a large territory -- it would be like an ant walking across the earth,\u0022 explained Zamir.\n\u003C\/p\u003E\n\u003Cp\u003ELooking more closely at the edge cells, the researchers found strong evidence that expansion of the edge cell population was due exclusively to cells relocating from an interior region to the edge as the embryo expanded. The cells located at the free edge generated the bulk of the traction force necessary for expansion and towed the cells within the interior of the epithelium.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022These experiments confirm that edge cell proliferation is not the primary mechanism for expansion of the edge cell population,\u0022 noted Zamir. \u0022And our observation of epithelial-to-mesenchymal transition in the edge cells explains how these epithelial cells might be changing phenotype to become migratory in this rapidly expanding sheet.\u0022\n\u003C\/p\u003E\n\u003Cp\u003ETo determine if this study\u0027s findings are indeed unique to the avian embryo, Zamir plans to conduct further studies to characterize protein expression and cell migration in Xenopus and zebrafish.\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts:\u003C\/strong\u003E Abby Robinson (abby@innovate.gatech.edu; 404-385-3364) or John Toon (jtoon@gatech.edu; 404-894-6986)\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Abby Robinson\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Study Investigates Process Involved in Cancer and Wound Healing"}],"field_summary":[{"value":"\u003Cp\u003EAvian embryos could become model organisms used to study a specific type of cell migration called epiboly, a developmental process involving mass movement of cells as a sheet that is linked with medical conditions that include wound healing and cancer.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Bird embryos provide insights into cancer and wound healing."}],"uid":"27206","created_gmt":"2011-03-23 00:00:00","changed_gmt":"2016-10-08 03:08:26","author":"Abby Vogel Robinson","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-03-23T00:00:00-04:00","iso_date":"2011-03-23T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"65120":{"id":"65120","type":"image","title":"Quail eggs","body":null,"created":"1449176801","gmt_created":"2015-12-03 21:06:41","changed":"1475894574","gmt_changed":"2016-10-08 02:42:54","alt":"Quail eggs","file":{"fid":"192170","name":"trq14296.jpg","image_path":"\/sites\/default\/files\/images\/trq14296_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/trq14296_0.jpg","mime":"image\/jpeg","size":36918,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/trq14296_0.jpg?itok=5yg6dnbv"}},"65121":{"id":"65121","type":"image","title":"vimentin expression","body":null,"created":"1449176801","gmt_created":"2015-12-03 21:06:41","changed":"1475894574","gmt_changed":"2016-10-08 02:42:54","alt":"vimentin expression","file":{"fid":"192171","name":"ttm10064.jpg","image_path":"\/sites\/default\/files\/images\/ttm10064_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/ttm10064_0.jpg","mime":"image\/jpeg","size":412574,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/ttm10064_0.jpg?itok=wGHoaqqb"}},"65122":{"id":"65122","type":"image","title":"BrDU cell proliferation","body":null,"created":"1449176801","gmt_created":"2015-12-03 21:06:41","changed":"1475894574","gmt_changed":"2016-10-08 02:42:54","alt":"BrDU cell proliferation","file":{"fid":"192172","name":"tqj10240.jpg","image_path":"\/sites\/default\/files\/images\/tqj10240_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tqj10240_0.jpg","mime":"image\/jpeg","size":811391,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tqj10240_0.jpg?itok=V0B1dG8e"}}},"media_ids":["65120","65121","65122"],"related_links":[{"url":"http:\/\/dx.doi.org\/10.1002\/dvdy.22607","title":"Developmental Dynamics paper"},{"url":"http:\/\/www.me.gatech.edu\/faculty\/zamir.shtml","title":"Evan Zamir"},{"url":"http:\/\/www.me.gatech.edu\/faculty\/garcia.shtml","title":"Andres Garcia"},{"url":"http:\/\/www.me.gatech.edu\/","title":"George W. Woodruff School of Mechanical Engineering"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"140","name":"Cancer Research"},{"id":"145","name":"Engineering"},{"id":"135","name":"Research"}],"keywords":[{"id":"539","name":"Andres Garcia"},{"id":"4619","name":"avian"},{"id":"12460","name":"avian embryo"},{"id":"12467","name":"b-catenin"},{"id":"385","name":"cancer"},{"id":"594","name":"college of engineering"},{"id":"12466","name":"cytokeratin"},{"id":"351","name":"development"},{"id":"12471","name":"Developmental Biology"},{"id":"12468","name":"e-cadherin"},{"id":"9228","name":"embryo"},{"id":"12472","name":"Embryo Development"},{"id":"12464","name":"epiboly"},{"id":"12459","name":"Evan Zamir"},{"id":"12469","name":"Laminin"},{"id":"10364","name":"Metastasis"},{"id":"12461","name":"Quail"},{"id":"12462","name":"quail embryo"},{"id":"167377","name":"School of Mechanical Engineering"},{"id":"12470","name":"tumor cell migration"},{"id":"12465","name":"vimentin"},{"id":"12463","name":"Wound Healing"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EAbby Robinson\u003C\/strong\u003E\u003Cbr \/\u003EResearch News and Publications\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=avogel6\u0022\u003EContact Abby Robinson\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-385-3364\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["abby@innovate.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}