Terphenylquinone inhibitors of the src protein tyrosine kinase from Stilbella sp.

Three new secondary metabolites, 2,5-dihydroxy-3-(3,4-dihydroxyphenyl)-6-phenyl-1,4-benzoquinone (3), 2,5-dihydroxy-3-phenyl-6-(3,4,5-trihydroxyphenyl)-1,4-benzoquinone (4), and 2,7,8-trihydroxy-3-phenyl-1,4-dibenzofurandione (5), as well as two known natural products were isolated from the fungus Stilbella sp. strain 1586. The structures of these compounds were established by spectroscopic and chemical methods. The terphenylquinones 3-5 exhibited significant activity against human src protein tyrosine kinase.

Epiplakin gene analysis in mouse reveals a single exon encoding a 725-kDa protein with expression restricted to epithelial tissues.

Based on cDNA cloning and sequencing, human epiplakin has been classified as a member of the plakin protein family of cytolinkers. We report here the characterization of the mouse epiplakin gene locus and the isolation of full-length mouse epiplakin cDNA using BAC vectors. We found that the protein is encoded by a single remarkably large exon (>20 kb) that consists of a series of 0.8-1.5-kb-long DNA repeats, eight of which are virtually identical. Consequently, mouse epiplakin contains 16 plakin repeat domains, three more than reported for the human protein and eight more than predicted for the mouse protein based on the contig characterized by the Mouse Genome Sequencing Consortium. Using antibodies raised to a highly conserved repeating epiplakin sequence domain, we show that the protein in cells is expressed in its full length (725 kDa), and we provide evidence that the size of human epiplakin previously may have been underestimated. In addition we show on transcript and protein levels that epiplakin is restricted to epithelial tissues and that its gene maps to mouse chromosome 15 (human chromosome 8). This study lays the groundwork for future genetic approaches aimed at defining the biological role of this unique protein.