Robert K. Ho

Research Summary
The zebrafish, Danio rerio, is a relatively simple vertebrate whose potential as a model system for developmental studies is only recently being realized. Embryos are easy to obtain in large numbers, develop external to the mother in fresh water and are optically transparent throughout the early stages of development. These features make the zebrafish embryo easily accessible to experimental manipulations such as the microinjection of lineage tracer molecules, cell ablations and cell transplantation. In addition to being an excellent embryological preparation, the zebrafish has an extensive history of genetic analyses and many interesting mutations have already been isolated. The ability to combine a workable genetics with an accessible embryology is perhaps the most advantageous feature of working with the zebrafish and has provided us with many novel insights into vertebrate development. The theme of the work being performed in the laboratory is to address classical problems of vertebrate embryogenesis using modern techniques in the zebrafish embryo. The general goal is to gain insights into the cellular, molecular and genetic mechanisms leading to the assignment of cell fate and, ultimately, to the formation of a complex vertebrate body plan. We are especially interested in the processes leading to the specification of the embryonic body axes and how the movements of individual cells within the embryo influence/correlate with cell fate decisions.
  1. Tbx5a and Tbx5b paralogues act in combination to control separate vectors of migration in the fin field of zebrafish. Dev Biol. 2022 01; 481:201-214. View in: PubMed

  2. Anterior lateral plate mesoderm gives rise to multiple tissues and requires tbx5a function in left-right asymmetry, migration dynamics, and cell specification of late-addition cardiac cells. Dev Biol. 2021 04; 472:52-66. View in: PubMed

  3. The Cdx transcription factors and retinoic acid play parallel roles in antero-posterior position of the pectoral fin field during gastrulation. Mech Dev. 2020 12; 164:103644. View in: PubMed

  4. Adipose fin development and its relation to the evolutionary origins of median fins. Sci Rep. 2019 01 24; 9(1):512. View in: PubMed

  5. A transcriptomics analysis of the Tbx5 paralogues in zebrafish. PLoS One. 2018; 13(12):e0208766. View in: PubMed

  6. Evolutionarily conserved Tbx5-Wnt2/2b pathway orchestrates cardiopulmonary development. Proc Natl Acad Sci U S A. 2018 11 06; 115(45):E10615-E10624. View in: PubMed

  7. m6A-dependent maternal mRNA clearance facilitates zebrafish maternal-to-zygotic transition. Nature. 2017 02 23; 542(7642):475-478. View in: PubMed

  8. CDX4 and retinoic acid interact to position the hindbrain-spinal cord transition. Dev Biol. 2016 Feb 15; 410(2):178-189. View in: PubMed

  9. Asymmetric cell convergence-driven zebrafish fin bud initiation and pre-pattern requires Tbx5a control of a mesenchymal Fgf signal. Development. 2015 Dec 15; 142(24):4329-39. View in: PubMed

  10. Zebrafish Tbx16 regulates intermediate mesoderm cell fate by attenuating Fgf activity. Dev Biol. 2013 Nov 01; 383(1):75-89. View in: PubMed

  11. Movement and function of the pectoral fins of the larval zebrafish (Danio rerio) during slow swimming. J Exp Biol. 2011 Sep 15; 214(Pt 18):3111-23. View in: PubMed

  12. Spatio-temporal regulation of Wnt and retinoic acid signaling by tbx16/spadetail during zebrafish mesoderm differentiation. BMC Genomics. 2010 Sep 09; 11:492. View in: PubMed

  13. The autism susceptibility gene met regulates zebrafish cerebellar development and facial motor neuron migration. Dev Biol. 2009 Nov 01; 335(1):78-92. View in: PubMed

  14. Fate mapping embryonic blood in zebrafish: multi- and unipotential lineages are segregated at gastrulation. Dev Cell. 2009 May; 16(5):744-55. View in: PubMed

  15. Tri-phasic expression of posterior Hox genes during development of pectoral fins in zebrafish: implications for the evolution of vertebrate paired appendages. Dev Biol. 2008 Oct 01; 322(1):220-33. View in: PubMed

  16. Repression of the hindbrain developmental program by Cdx factors is required for the specification of the vertebrate spinal cord. Development. 2007 Jun; 134(11):2147-58. View in: PubMed

  17. A new time-scale for ray-finned fish evolution. Proc Biol Sci. 2007 Feb 22; 274(1609):489-98. View in: PubMed

  18. Fog1 is required for cardiac looping in zebrafish. Dev Biol. 2006 Jan 15; 289(2):482-93. View in: PubMed

  19. Generation of segment polarity in the paraxial mesoderm of the zebrafish through a T-box-dependent inductive event. Dev Biol. 2005 Jul 01; 283(1):204-14. View in: PubMed

  20. Cooperative function of deltaC and her7 in anterior segment formation. Dev Biol. 2005 Apr 01; 280(1):133-49. View in: PubMed

  21. T-box gene eomesodermin and the homeobox-containing Mix/Bix gene mtx2 regulate epiboly movements in the zebrafish. Dev Dyn. 2005 May; 233(1):105-14. View in: PubMed

  22. A crucial interaction between embryonic red blood cell progenitors and paraxial mesoderm revealed in spadetail embryos. Dev Cell. 2004 Aug; 7(2):251-62. View in: PubMed

  23. The maternally expressed zebrafish T-box gene eomesodermin regulates organizer formation. Development. 2003 Nov; 130(22):5503-17. View in: PubMed

  24. The zebrafish van gogh mutation disrupts tbx1, which is involved in the DiGeorge deletion syndrome in humans. Development. 2003 Oct; 130(20):5043-52. View in: PubMed

  25. T-box gene tbx5 is essential for formation of the pectoral limb bud. Nature. 2002 Jun 13; 417(6890):754-8. View in: PubMed

  26. Zebrafish SPI-1 (PU.1) marks a site of myeloid development independent of primitive erythropoiesis: implications for axial patterning. Dev Biol. 2002 Jun 15; 246(2):274-95. View in: PubMed

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  28. The elongation factors Pandora/Spt6 and Foggy/Spt5 promote transcription in the zebrafish embryo. Development. 2002 Apr; 129(7):1623-32. View in: PubMed

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  30. Additional hox clusters in the zebrafish: divergent expression patterns belie equivalent activities of duplicate hoxB5 genes. Evol Dev. 2001 May-Jun; 3(3):127-44. View in: PubMed

  31. Zebrafish lunatic fringe demarcates segmental boundaries. Mech Dev. 2001 Jul; 105(1-2):175-80. View in: PubMed

  32. tbx20, a new vertebrate T-box gene expressed in the cranial motor neurons and developing cardiovascular structures in zebrafish. Mech Dev. 2000 Jul; 95(1-2):253-8. View in: PubMed

  33. Too much interference: injection of double-stranded RNA has nonspecific effects in the zebrafish embryo. Dev Biol. 2000 Aug 01; 224(1):20-8. View in: PubMed

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  38. Zebrafish stat3 is expressed in restricted tissues during embryogenesis and stat1 rescues cytokine signaling in a STAT1-deficient human cell line. Dev Dyn. 1999 Aug; 215(4):352-70. View in: PubMed

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  42. Hox gene expression reveals regionalization along the anteroposterior axis of the zebrafish notochord. Dev Genes Evol. 1998 Nov; 208(9):517-22. View in: PubMed

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