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Free keywords:
Amino Acid Sequence
Animals
Chromosome Mapping
Cloning, Molecular
Coatomer Protein
Corticotropin-Releasing Hormone/genetics
Cosmids
Culture Techniques
DNA-Binding Proteins/genetics
Fishes/*genetics
*Genomic Imprinting
Humans
In Situ Hybridization, Fluorescence
Mice
Molecular Sequence Data
Multigene Family
Proteins/*genetics
Sequence Analysis, DNA
Sequence Homology, Amino Acid
Urocortins
Zebrafish
Abstract:
We isolated Fugu genomic clones using the human MEST (Mesoderm-Specific Transcript) cDNA as probe. Sequence analysis revealed the presence of MEST and three additional genes which show homology to plant DNBP (DNA-Binding Protein), vertebrate COPG2 (Coat Protein Gamma 2), as well as to human and mouse UCN (Urocortin). Structures of Fugu and human MEST, COPG2 and UCN genes are very similar. Since MEST and COPG2 are neighboring genes on human chromosome 7q32, we can conclude that we identified their orthologs and that linkage of these genes is evolutionarily conserved in vertebrates. Unlike human MEST which underlies isoform-specific imprinting and is methylated in a parent-of-origin-specific fashion, the CpG island of the Fugu ortholog is completely methylated. The translation start of Fugu MEST is identical to the non-imprinted human isoform which is in good agreement with the assumption that genomic imprinting is restricted to mammals. Comparative mapping of these genes by fluorescence in-situ hybridization to metaphase chromosomes of Fugu rubripes and Tetraodon nigroviridis showed clear signals on one of the smallest acrocentric chromosomal pairs, which in Fugu, can be easily classified by its unique triangular shape.
