title: Detection of differential fetal and adult expression of chloride intracellular channel 4 (CLIC4) protein by analysis of a green fluorescent protein knock-in mouse line.
abstract: BACKGROUND
  Chloride Intracellular Channel 4 (CLIC4) is one of seven members in the closely related CLIC protein family. CLIC4 is involved in multiple cellular processes including apoptosis, cellular differentiation, inflammation and endothelial tubulogenesis. Despite over a decade of research, no comprehensive in situ expression analysis of CLIC4 in a living organism has been reported. In order to fulfill this goal, we generated a knock-in mouse to express Green Fluorescent Protein (GFP) from the CLIC4 locus, thus substituting the GFP coding region for CLIC4. We used GFP protein expression to eliminate cross reaction with other CLIC family members.
  
  
  RESULTS
  We analyzed CLIC4 expression during embryonic development and adult organs. During mid and late gestation, CLIC4 expression is modulated particularly in fetal brain, heart, thymus, liver and kidney as well as in developing brown adipose tissue and stratifying epidermis. In the adult mouse, CLIC4 is highly expressed globally in vascular endothelial cells as well as in liver, lung alveolar septae, pancreatic acini, spermatogonia, renal proximal tubules, cardiomyocytes and thymic epithelial cells. Neural expression included axonal tracks, olfactory bulb, Purkinje cell layer and dentate gyrus. Renal CLIC4 expression was most pronounced in proximal tubules, although altered renal function was not detected in the absence of CLIC4. Myeloid cells and B cells of the spleen are rich in CLIC4 expression as are CD4 and CD8 positive T cells.
  
  
  CONCLUSIONS
  In a comprehensive study detailing CLIC4 expression in situ in a mouse model that excludes cross reaction with other family members, we were able to document previously unreported expression for CLIC4 in developing fetus, particularly the brain. In addition, compartmentalized expression of CLIC4 in specific adult tissues and cells provides a focus to explore potential functions of this protein not addressed previously.
authors.forename: Vc
authors.initials: V
authors.lastname: Padmakumar
authors.forename: Katelyn E
authors.initials: KE
authors.lastname: Masiuk
authors.forename: Dror
authors.initials: D
authors.lastname: Luger
authors.forename: Christina
authors.initials: C
authors.lastname: Lee
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Coppola
authors.forename: Lino
authors.initials: L
authors.lastname: Tessarollo
authors.forename: Shelley B
authors.initials: SB
authors.lastname: Hoover
authors.forename: Irina
authors.initials: I
authors.lastname: Karavanova
authors.forename: Andres
authors.initials: A
authors.lastname: Buonanno
authors.forename: R Mark
authors.initials: RM
authors.lastname: Simpson
authors.affiliation: Laboratory of Cancer Biology and Genetics, National Cancer Institute, Bethesda, MD, USA. yuspas@mail.nih.gov.
authors.forename: Stuart H
authors.initials: SH
authors.lastname: Yuspa
mesh_terms: D002001:Adipose Tissue, Brown / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D018118:Chloride Channels / Q000235:genetics* / Q000378:metabolism; D004817:Epidermis / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D005318:Fetal Heart / Q000196:embryology / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics* / Q000378:metabolism; D006321:Heart / Q000254:growth & development; D015151:Immunoblotting; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007668:Kidney / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D008099:Liver / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013950:Thymus Gland / Q000196:embryology / Q000254:growth & development / Q000378:metabolism
chemical_list: C479423:CLIC protein, mouse; D018118:Chloride Channels; D024101:Mitochondrial Proteins; D049452:Green Fluorescent Proteins