title: Structural disorganization of pronephric glomerulus in zebrafish mpp5a/nagie oko mutant.
abstract: BACKGROUND
  The podocyte slit diaphragm (SD) is an essential component of the selective filtration barrier in the glomerulus. Several structural proteins required for formation and maintenance of SD have been identified; however, molecular mechanisms regulating these proteins are still limited.
  
  
  RESULTS
  Here, we demonstrate that MAGUK p55 subfamily member 5a (Mpp5a)/Nagie oko, a component of the Crb multi-protein complex, was colocalized with an SD-associated protein ZO-1 in the zebrafish pronephric glomerulus. To characterize the function of Mpp5a, zebrafish mpp5a(m520) mutant embryos, which are known to have defects in cardiac and neuronal morphogenesis, were analyzed. These mutants failed to merge the bilateral glomerular primordia and to form the glomerular capillary and mesangium, but the foot processes and SD showed normal appearance. The structural disorganization in the mpp5a(m520) mutant glomerulus was quite similar to that of a cardiac troponin T2a/tnnt2a/silent heart knockdown zebrafish, which exhibited circulatory failure due to lack of heart beating.
  
  
  CONCLUSIONS
  Mpp5a is not prerequisite to form podocyte slit diaphragm in the pronephric glomerular development in zebrafish. The structural disorganization of the pronephric glomerulus in the mpp5a(m520) mutant is likely to result from circulatory failure, rather than the anomaly of Mpp5a protein in the glomerulus.
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, USA.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ichimura
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Fukuyo
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Rebecca
authors.initials: R
authors.lastname: Powell
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Sakai
authors.forename: Tomoko
authors.initials: T
authors.lastname: Obara
mesh_terms: D000818:Animals; D055785:Gene Knockdown Techniques; D005920:Glomerular Mesangium / Q000196:embryology*; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism*; D006321:Heart / Q000196:embryology; D009154:Mutation; D050199:Podocytes / Q000378:metabolism*; D020107:Troponin T / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D020107:Troponin T; D029961:Zebrafish Proteins; C480681:tnnt2a protein, zebrafish; C501511:mpp5a protein, zebrafish; D006162:Guanylate Cyclase