Identification And Characterization Of A Highly Conserved Noncoding Element Associated With The Meis2 Gene; M2de2

Meis genes are conserved across species and play important roles in embryogenesis. There are four known members of the Meis gene family in vertebrates. Because of the genome duplication event in the teleost lineage, following the divergence from the lineage that would give rise to land vertebrates, zebrafish have two copies of the Meis2 gene, meis2a and meis2b, in contrast to the single Meis2 gene in tetrapods. We have identified four highly conserved noncoding elements (CNEs) in tetrapods that we hypothesize direct Meis2 expression. We have named these m2de1-4 (Meis2 downstream element). To date, only one of these has been identified in zebrafish. The purpose of this study was to characterize m2de2 using zebrafish as a model. Using the Tol2 system, expression constructs containing mouse m2de2 that drove expression of eGFP through the cfos minimal promoter were microinjected into zebrafish embryos at the single cell stage. Confocal microscopy was used to determine eGFP expression at different time points during development. Expression was observed in specific neurons in the brain of the developing zebrafish embryos in a pattern consistent with that observed for the murine Meis2 gene. eGFP was also observed in developing muscle fibers in the trunk of zebrafish embryos.