Polaris and Polycystin-2 in dorsal forerunner cells and Kupffer's vesicle are required for specification of the zebrafish left-right axis

Bisgrove, B.W., Snarr, B.S., Emrazian, A., and Yost, H.J.
Developmental Biology   287(2): 274-288 (Journal)
Registered Authors
Bisgrove, Brent, Snarr, Brian, Yost, H. Joseph
polaris, polycystin-2, Cilia, Left–right asymmetry, Kupffer's vesicle
MeSH Terms
  • Animals
  • Body Patterning
  • Cilia/metabolism
  • Gene Expression Regulation, Developmental
  • Left-Right Determination Factors
  • Membrane Proteins/genetics
  • Membrane Proteins/metabolism*
  • Mice
  • Mutation
  • TRPP Cation Channels
  • Transforming Growth Factor beta/metabolism
  • Tumor Suppressor Proteins/genetics
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Zebrafish/metabolism
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
16216239 Full text @ Dev. Biol.
Recently, it has become clear that motile cilia play a central role in initiating a left-sided signaling cascade important in establishing the LR axis during mouse and zebrafish embryogenesis. Two genes proposed to be important in this cilia-mediated signaling cascade are polaris and polycystin-2 (pkd2). Polaris is involved in ciliary assembly, while Pkd2 is proposed to function as a Ca(2+)-permeable cation channel. We have cloned zebrafish homologues of polaris and pkd2. Both genes are expressed in dorsal forerunner cells (DFCs) from gastrulation to early somite stages when these cells form a ciliated Kupffer's vesicle (KV). Morpholino-mediated knockdown of Polaris or Pkd2 in zebrafish results in misexpression of left-side-specific genes, including southpaw, lefty1 and lefty2, and randomization of heart and gut looping. By targeting morpholinos to DFCs/KV, we show that polaris and pkd2 are required in DFCs/KV for normal LR development. Polaris morphants have defects in KV cilia, suggesting that the laterality phenotype is due to problems in cilia function per se. We further show that expression of polaris and pkd2 is dependent on the T-box transcription factors no tail and spadetail, respectively, suggesting that these genes have a previously unrecognized role in regulating ciliary structure and function. Our data suggest that the functions of polaris and pkd2 in LR patterning are conserved between zebrafish and mice and that Kupffer's vesicle functions as a ciliated organ of asymmetry.
Genes / Markers
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Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes