Cloning and sequence comparison of the mouse, human, and chickenengrailedgenes reveal potential functional domains and regulatory regions

摘要

AbstractWe have isolated and characterized genomic DNA clones for the human and chicken homologues of the mouseEn‐1andEn‐2genes and determined the genomic structure and predicted protein sequences of bothEngenes in all three species. Comparison of these vertebrateEnsequences with theXenopus En‐2(Hemmati‐Brivanlouet al., 1991) and invertebrateengrailed‐like genes showed that the two previously identified highly conserved regions within theEnprotein reviewed in Joyner and Hanks, 1991 can be divided into five distinct subregions, designated EH1 to EH5. Sequences 5′ and 3′ to the predicted coding regions of the vertebrateEngenes were also analyzed in an attempt to identify cis‐acting DNA sequences important for the regulation ofEngene expression. Considerable sequence similarity was found between the mouse and human homologues both within the putative 5′ and 3′ untranslated as well as 5′ flanking regions. Between the mouse andXenopus En‐2genes, shorter stretches of sequence similarity were found within the 3′ untranslated region. The 5′ untranslated regions of the mouse, chicken andXenopus En‐2genes, however, showed no similarly conserved stretches. In a preliminary analysis of the expression pattern of the humanEngenes,En‐2protein and RNA were detected in the embryonic and adult cerebellum respectively and not in other tissues tested. These patterns are analogous to those seen in other vertebrates. Taken together these results further strengthen the suggestion thatEngene function and regulation has been conserved throughout vertebrate evolution and along with the five highly conserved regions within theEnprotein, raise an interesting question about the presence of conserved genetic p