title: Depletion of the IKBKAP ortholog in zebrafish leads to hirschsprung disease-like phenotype.
abstract: OBJECTIVE
  To investigate the role of IKBKAP (inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase complex-associated protein) in the development of enteric nervous system (ENS) and Hirschsprung disease (HSCR).
  
  
  METHODS
  In this study, we injected a morpholino that blocked the translation of ikbkap protein to 1-cell stage zebrafish embryos. The phenotype in the ENS was analysed by antibody staining of the pan-neuronal marker HuC/D followed by enteric neuron counting. The mean numbers of enteric neurons were compared between the morphant and the control. We also studied the expressions of ret and phox2bb, which are involved in ENS development, in the ikbkap morpholino injected embryos by quantitative reverse transcriptase polymerase chain reaction and compared them with the control.
  
  
  RESULTS
  We observed aganglionosis (χ2, P<0.01) and a reduced number of enteric neurons (38.8±9.9 vs 50.2±17.3, P<0.05) in the zebrafish embryos injected with ikbkap translation-blocking morpholino (morphant) when compared with the control embryos. Specificity of the morpholino was confirmed by similar results obtained using a second non-overlapping morpholino that blocked the translation of ikbkap. We further studied the morphant by analysing the expression levels of genes involved in ENS development such as ret, phox2bb and sox10, and found that phox2bb, the ortholog of human PHOX2B, was significantly down-regulated (0.51±0.15 vs 1.00±0, P<0.05). Although we also observed a reduction in the expression of ret, the difference was not significant.
  
  
  CONCLUSIONS
  Loss of IKBKAP contributed to HSCR as demonstrated by functional analysis in zebrafish embryos.
authors.affiliation: William Wai-Chun Cheng, Man-Ting So, Vincent Chi-Hang Lui, Paul Kwong-Hang Tam, Maria-Mercè Garcia-Barcelo, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China.
authors.forename: William Wai-Chun
authors.initials: WW
authors.lastname: Cheng
authors.affiliation: William Wai-Chun Cheng, Man-Ting So, Vincent Chi-Hang Lui, Paul Kwong-Hang Tam, Maria-Mercè Garcia-Barcelo, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China.
authors.forename: Clara Sze-Man
authors.initials: CS
authors.lastname: Tang
authors.affiliation: William Wai-Chun Cheng, Man-Ting So, Vincent Chi-Hang Lui, Paul Kwong-Hang Tam, Maria-Mercè Garcia-Barcelo, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China.
authors.forename: Hong-Sheng
authors.initials: HS
authors.lastname: Gui
authors.affiliation: William Wai-Chun Cheng, Man-Ting So, Vincent Chi-Hang Lui, Paul Kwong-Hang Tam, Maria-Mercè Garcia-Barcelo, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China.
authors.forename: Man-Ting
authors.initials: MT
authors.lastname: So
authors.affiliation: William Wai-Chun Cheng, Man-Ting So, Vincent Chi-Hang Lui, Paul Kwong-Hang Tam, Maria-Mercè Garcia-Barcelo, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China.
authors.forename: Vincent Chi-Hang
authors.initials: VC
authors.lastname: Lui
authors.affiliation: William Wai-Chun Cheng, Man-Ting So, Vincent Chi-Hang Lui, Paul Kwong-Hang Tam, Maria-Mercè Garcia-Barcelo, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China.
authors.forename: Paul Kwong-Hang
authors.initials: PK
authors.lastname: Tam
authors.affiliation: William Wai-Chun Cheng, Man-Ting So, Vincent Chi-Hang Lui, Paul Kwong-Hang Tam, Maria-Mercè Garcia-Barcelo, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China.
authors.forename: Maria-Mercè
authors.initials: MM
authors.lastname: Garcia-Barcelo
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D004195:Disease Models, Animal; D017615:Enteric Nervous System / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D020022:Genetic Predisposition to Disease; D006627:Hirschsprung Disease / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D060172:Morpholinos / Q000008:administration & dosage; D010641:Phenotype; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D018398:Homeodomain Proteins; D060172:Morpholinos; C109220:NBPhox protein; D014157:Transcription Factors; D029961:Zebrafish Proteins; C000601592:elp1 protein, zebrafish; D051096:Proto-Oncogene Proteins c-ret; C546313:Ret protein, zebrafish
keywords: Enteric nervous system; Hirschsprung disease; IKBKAP; Morpholinos; Zebrafish