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Presenting Author(s) Carolina Minguillon
Abstract Title The role of the "limb-identity" genes in initiation of limb outgrowth.
Full author List Carolina Minguillon, Jo del Buono and Malcolm Logan
Text of abstract

Many of the factors identified to have roles in limb patterning are expressed in identical patterns in fore and hindlimb buds. Nevertheless, the structures they ultimately form are morphologically distinct. We are interested in understanding the molecular basis of the differential response of cells in the fore and hindlimbs to common signalling molecules and are characterising some of the genetic elements that account for these morphological differences. Relatively few genes that are differentially expressed in fore or hindlimbs have been identified. However, two T-box transcription factors, Tbx5 and Tbx4, are expressed exclusively in either forelimb or hindlimb buds respectively. In addition, a paired-related homeodomain transcription factor, Pitx1, is expressed in the developing hindlimb but not the developing forelimb. Misexpression experiments in the chick have suggested that these genes are involved in specification of limb-type identity. In contrast, gene deletion experiments in the mouse have implicated the same genes in limb bud outgrowth.

We are using Cre/lox technology in combination with transgenic methods in the mouse to disrupt Tbx5 function in the forelimb and replace it with either Tbx4, Pitx1 or both genes to test the properties of these factors in (i) limb outgrowth and (ii) specification of limb-type identity.

Which session is your work most relevant to: Limb initiation