title: Ezrin is highly expressed in early thymocytes, but dispensable for T cell development in mice.
abstract: BACKGROUND
  Ezrin/radixin/moesin (ERM) proteins are highly homologous proteins that function to link cargo molecules to the actin cytoskeleton. Ezrin and moesin are both expressed in mature lymphocytes, where they play overlapping roles in cell signaling and polarity, but their role in lymphoid development has not been explored.
  
  
  RESULTS
  We characterized ERM protein expression in lymphoid tissues and analyzed the requirement for ezrin expression in lymphoid development. In wildtype mice, we found that most cells in the spleen and thymus express both ezrin and moesin, but little radixin. ERM protein expression in the thymus was differentially regulated, such that ezrin expression was highest in immature thymocytes and diminished during T cell development. In contrast, moesin expression was low in early thymocytes and upregulated during T cell development. Mice bearing a germline deletion of ezrin exhibited profound defects in the size and cellularity of the spleen and thymus, abnormal thymic architecture, diminished hematopoiesis, and increased proportions of granulocytic precursors. Further analysis using fetal liver chimeras and thymic transplants showed that ezrin expression is dispensable in hematopoietic and stromal lineages, and that most of the defects in lymphoid development in ezrin(-/-) mice likely arise as a consequence of nutritional stress.
  
  
  CONCLUSIONS
  We conclude that despite high expression in lymphoid precursor cells, ezrin is dispensable for lymphoid development, most likely due to redundancy with moesin.
authors.affiliation: Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America.
authors.forename: Meredith H
authors.initials: MH
authors.lastname: Shaffer
authors.forename: Yanping
authors.initials: Y
authors.lastname: Huang
authors.forename: Evann
authors.initials: E
authors.lastname: Corbo
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Wu
authors.forename: Marielena
authors.initials: M
authors.lastname: Velez
authors.forename: John K
authors.initials: JK
authors.lastname: Choi
authors.forename: Ichiko
authors.initials: I
authors.lastname: Saotome
authors.forename: Judy L
authors.initials: JL
authors.lastname: Cannon
authors.forename: Andrea I
authors.initials: AI
authors.lastname: McClatchey
authors.forename: Anne I
authors.initials: AI
authors.lastname: Sperling
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Maltzman
authors.forename: Paula M
authors.initials: PM
authors.lastname: Oliver
authors.forename: Avinash
authors.initials: A
authors.lastname: Bhandoola
authors.forename: Terri M
authors.initials: TM
authors.lastname: Laufer
authors.forename: Janis K
authors.initials: JK
authors.lastname: Burkhardt
mesh_terms: D000818:Animals; D002452:Cell Count; D003598:Cytoskeletal Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006410:Hematopoiesis; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation; D000099149:Ezrin
chemical_list: D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D000099149:Ezrin; C071058:moesin; C071776:radixin
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