Volume 4 Supplement 1

Proceedings of the Second International Cilia in Development and Disease Scientific Conference (2014)

Open Access

Does stopping left-right nodal flow mirror impaired mechanosensation in the left-right organizer?

  • R Jacinto1,
  • P Sampaio1,
  • M Roxo-Rosa1 and
  • SS Lopes1
Cilia20154(Suppl 1):P39

DOI: 10.1186/2046-2530-4-S1-P39

Published: 13 July 2015

Background

In most vertebrates organ asymmetries arise in early development through the left-right organizer (LRO). LRO ciliated cells induce a leftward fluid flow responsible for the asymmetric expression of Nodal pathway genes in tissues that will originate internal organs. We have recently published that charon/dand5 transcription is an early flow target in zebrafish by being expressed in the LRO, first symmetrically and later asymmetrically to the right where the fluid flow is weaker. We showed that absence of flow originates symmetric charon expression [1]. Pkd2 has been reported as part of a mechanosensor complex that senses flow and induces a calcium inward flux in kidney cells [2] and mouse LRO [3]. In agreement, mouse and zebrafish Pkd2 mutants have LR defects [4, 5].

Objective

Determine if impaired mechanosensing renders the same charon/dand5 phenotype as absent flow.

Methods

We injected two morpholinos in zebrafish embryos: a dnah7-MO to stop cilia movement [1] and a pkd2-MO. We also co-injected both. We recorded flow by particle analysis, quantified Pkd2 expression and correlated these with charon/dand5 expression patterns by in situ hybridization and qRT-PCR.

Results

50-60% of injected embryos have symmetric charon/dand5 expression when flow is low and homogeneous or when Pkd2 is absent from LRO ciliary membrane. We will show if charon/dand5 quantification by qRT-PCR is also similar. When both flow and Pkd2 are impaired, 80% of embryos showed symmetric charon/dand5, which indicates a synergistic effect.

Conclusion

Although no flow and no Pkd2 have virtually the same phenotype, there seems to be a positive epistasis when both are affected.

Acknowlegements

Supported by FCT-ANR/BEX-BID/0153/2012 grant and PD/BD/52420/2013 PhD scholarship.

Authors’ Affiliations

(1)
Chronic Diseases Research Center, CEDOC, NOVA Medical School / Faculdade de Ciências Médicas, Universidade Nova de Lisboa

References

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Copyright

© Jacinto et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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