Meeting Abstract

31.5  Friday, Jan. 4  Generation of a Xenopus col2a1 reporter for cartilage-specific transgene expression KERNEY, Ryan; Dalhousie University ryankerney@gmail.com

This study examines enhancer regions of the collagen 2 alpha1 (col2a1) first intron in Xenopus tropicalis that are capable of driving transgenic EGFP expression in Xenopus laevis when connected to a minimal promoter. The EGFP expressions of various col2a1 reporter constructs in transgenic tadpoles and frogs are compared to the mRNA expression of col2a1 in situ hybridizations. The 3′ portion of the intron, when connected to a short section of the upstream promoter, is capable of driving EGFP expression in a subset of axial myocytes. Transgene expression in these myocytes correlates with early col2a1 mRNA expression in the lateral plate mesoderm, which contains axial myocyte precursor cells. The 5′ portion of the intron, also connected to the promoter sequence, is capable of driving EGFP expression in larval chondrocytes. Col2a1 mRNA is strongly expressed in chondrocytes, as the type-II collagen protein product is the dominant collagen of cartilage. This cartilaginous expression of EGFP is replicated by a truncated 665 base pair (bp) intronic region, but not by a further truncated 153 bp region. All three intron segments contain a region that aligns with the corresponding mouse intron in pairwise LAGAN/Vista and MEME analyses. The creation of cartilage-specific gene expression provides a new tool for further studies of chondrocyte fate mapping and gene misexpression, and will allow new research in the molecular mechanisms of anuran skeletal development.