Douglas Houston

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Doug Houston
PhD, University of Miami, 1999
Email: Phone:
(319) 335-1316
Lab Phone:
(319) 335-1317
257 Biology Building
129 East Jefferson St., Iowa City, IA 52242-1324
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Research Areas

Research Summary

Localized molecules and maternal signalling pathways in vertebrate development

In many vertebrate eggs, fertilization initiates cortical/cytoplasmic rearrangements (cortical rotation), resulting in the transport of critical determinants to the future dorsal side. In the frog Xenopus, this event is mediated by microtubules and causes the localized activation of the Wnt signaling pathway dorsally. Wnts are key growth factors involved in many aspects of development and are often misregulated in cancers and other diseases. Similar cytoplasmic localizations and Wnt activation occur in many chordate embryos, suggesting a deeply conserved mechanism for patterning early embryos. Our lab is currently pursuing several main avenues of investigation:  (1) identifying and characterizing the roles of asymmetrically-localized mRNAs and proteins in early dorsal axis formation, (2) elucidating mechanisms of microtubule assembly and orientation during cortical rotation and (3) determining how Wnt signaling is initiated and regulated on the dorsal side. We are addressing these questions using reverse-genetic antisense approaches in the amphibian Xenopus laevis. Additionally, we are  beginning to explore bona fide genetic manipulation of these processes in the genetically-tractable diploid frog species, Xenopus tropicalis

Keywords: developmental biology, germ cells, germ layer, localized RNAs, Wnt, axis formation, Xenopus

Selected Images

Fluorescent in situ hybridization showing trim36 RNA localization to the mitochondrial cloud of early stage Xenopus oocytes
Depletion of maternal trim36. (A) Quantitative real-time PCR of trim36 expression in oligo-injected oocytes. Samples were normalized to odc levels and displayed as a percentage relative to the uninjected oocyte (Un oo) sample. Oocytes were injected with 3.0 or 4.0 ng of trim36-3 oligo. (B) Phenotype of an uninjected stage 24 embryo. (C) Phenotypes of sibling trim36-depleted embryos. (D) In situ hybridization of sizzled (szl) in an uninjected control embryo. (E) szl expression in a trim36-depleted embyro.
Immunostaining of microtubules at 80 minutes post fertilization in control (Uninjected), trim36-depleted eggs.