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|Public on Jun 30, 2008
|Comparison of regenerating and non regenerating transgenic stage 52 Xenopus hind limbs
|Expression profiling by array
|Epimorphic regeneration is the process by which complete regeneration of a complex structure such as a limb occurs through production of a proliferating blastema. This type of regeneration is rare among vertebrates but does occur in the African clawed frog Xenopus laevis, traditionally a model organism for the study of early development. Xenopus tadpoles can regenerate tails, limb buds and the lens of the eye, although the ability of the latter two organs to regenerate diminishes with advancing developmental stage. Using a heat shock inducible transgene that remains silent unless activated, we have established a stable line of transgenic Xenopus in which the BMP inhibitor Noggin can be over-expressed at any time during development. We have previously shown that activation of this transgene blocks regeneration of the tail and limb of Xenopus tadpoles. In the current study, we have taken advantage of this transgenic line to directly compare gene expression in same stage regenerating vs. non-regenerating hind limb buds. Using Affymetrix gene chip analysis, we have identified genes whose expression levels are linked to regenerative success. These include the BMP inhibitor Gremlin and the stress protein Hsp60 (no blastema in zebrafish). Analysis of overrepresented Gene Ontology functional groupings suggests that successful regeneration in the Xenopus hind limb depends on induction of stress response pathways. Furthermore, as expected, genes involved in embryonic development and growth are also significantly over-represented in regenerating early hind limb buds.
Keywords: Differential expression, regeneration
|This series was used to identify differentially expressed genes between regenerating wild type stage 52 hind limb buds and those of their transgenic siblings which are blocked in BMP signalling and fail to regenerate. Two biological replicates of each type were examined. Each replicate is made up of dissected distal stump tissue from 20 hindlimbs 3 days after amputation. The single timepoint of 3 days was chosen to fall after wound healing had occurred but before re-differentiation and corresponds to the cone shaped blastema stage of successfull regenerates. BMP signalling is blocked using a single insertion transgene (N1) expressing noggin under the control of an inducible heat shock promoter, and all tadpoles are siblings derived from a single backcross to a wild type animal to minimise genetic variation.
|Beck CW, Pearl EJ, Barker D, Day RC
|Dec 06, 2007
|Last update date
|Mar 17, 2012
|University of Otago
|340 Great King Street
|[Xenopus_laevis] Affymetrix Xenopus laevis Genome Array
|TAR (of CEL, CHP)