bioRxiv preprint doi: https://doi.org/10.1101/534859; this version posted January 30, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. The lymphoid-associated interleukin 7 receptor (IL-7R) regulates tissue resident macrophage development Gabriel A. Leung1† Taylor Cool,2,3,† Clint H. Valencia4, Atesh Worthington2, Anna E. Beaudin4††*, E. Camilla Forsberg2††* 1 Quantitative and Systems Biology Program, University of California-Merced, Merced, CA, USA 2 Institute for the Biology of Stem Cells, University of California-Santa Cruz, Santa Cruz, CA, USA 3 Department of Biological Sciences, San Jose State University, San Jose, CA, USA 4 Molecular and Cell Biology Department, School of Natural Sciences, University of California- Merced, Merced, CA, USA † These authors contributed equally to this work. †† These authors contributed equally to this work. * Correspondence:
[email protected],
[email protected] bioRxiv preprint doi: https://doi.org/10.1101/534859; this version posted January 30, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Abstract The discovery of a fetal origin for tissue-resident macrophages (trMacs) has inspired an intense search for the mechanisms underlying their development. Here, we performed in vivo lineage tracing of cells with an expression history of IL-7Rα, a marker exclusively associated with the lymphoid lineage in adult hematopoiesis. Surprisingly, we found that IL7R-Cre labeled fetal- derived, adult trMacs. Labeling was almost complete in some tissues and partial in other organs.