title: Fgf4 is required for left-right patterning of visceral organs in zebrafish.
abstract: Fgf signaling plays essential roles in many developmental events. To investigate the roles of Fgf4 signaling in zebrafish development, we generated Fgf4 knockdown embryos by injection with Fgf4 antisense morpholino oligonucleotides. Randomized LR patterning of visceral organs including the liver, pancreas, and heart was observed in the knockdown embryos. Prominent expression of Fgf4 was observed in the posterior notochord and Kupffer's vesicle region in the early stages of segmentation. Lefty1, lefty2, southpaw, and pitx2 are known to play crucial roles in LR patterning of visceral organs. Fgf4 was essential for the expression of lefty1, which is necessary for the asymmetric expression of southpaw and pitx2 in the lateral plate mesoderm, in the posterior notochord, and the expression of lefty2 and lefty1 in the left cardiac field. Fgf8 is also known to be crucial for the formation of Kupffer's vesicle, which is needed for the LR patterning of visceral organs. In contrast, Fgf4 was required for the formation of cilia in Kupffer's vesicle, indicating that the role of Fgf4 in the LR patterning is quite distinct from that of Fgf8. The present findings indicate that Fgf4 plays a unique role in the LR patterning of visceral organs in zebrafish.
authors.affiliation: Department of Genetic Biochemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo, Kyoto 606-8501, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Noriko
authors.initials: N
authors.lastname: Miyakawa
authors.forename: Ayumi
authors.initials: A
authors.lastname: Miyake
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Itoh
mesh_terms: D000818:Animals; D019521:Body Patterning; D002923:Cilia / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D006321:Heart / Q000196:embryology; D055458:Left-Right Determination Factors; D008099:Liver / Q000196:embryology / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism; D009672:Notochord / Q000378:metabolism; D010179:Pancreas / Q000196:embryology / Q000378:metabolism; D014781:Viscera / Q000196:embryology* / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000378:metabolism*
chemical_list: C542564:Fgf4 protein, zebrafish; D055458:Left-Right Determination Factors; D029961:Zebrafish Proteins; C517774:fgf8a protein, zebrafish; C117508:lft1 protein, zebrafish; D005346:Fibroblast Growth Factors