An in vivo RNAi screen identifies components of the JAK/STAT signaling that regulate cell migration. Afsoon Saadin, Michelle Starz-Gaiano. Biological Sciences, UMBC, Baltimore, MD.

   The Janus Kinase and Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathway is involved in essential biological processes including cell fate determination, cell migration, cell proliferation, normal function of immune system, and stem cell maintenance. Out of different events that can be regulated by JAK/STAT signaling, cell migration is particularly interesting since it is not only required for normal embryonic development but can also lead to detrimental outcomes, such as tumor metastasis. Migration of a cluster of cells termed border cells in the Drosophila ovary is an excellent example of collective cell migration, which resembles metastasis of some carcinoma cells. Border cells arise within the follicular epithelium, and are required to migrate to the oocyte to contribute to a fertilizable egg. The requirement for the well-conserved components of STAT signaling pathway, including the activating cytokine, its receptor, JAK, STAT, SOCS and APONTIC, during border cell migration is well-studied, however, the functions of other potential regulators of the pathway during this process are not yet known. To find new components of the pathway that govern cell migration, we knocked down predicted STAT modulators using RNAi expression in follicle cells, and assayed for defective cell movement. We have identified a number of candidate genes that function during cell invasion, and these are currently being further characterized.