ABSTRACT
We report the precise mapping and characterization of ZIRTL (zinc-iron regulated transporter-like) gene, the first mammalian member of an extensive family of divalent metal ion transporters, comprising IRT1 and ZIP1, ZIP2, ZIP3, and ZIP4 in plants and ZRT1 and ZRT2 in yeast. The human gene maps at the telomeric end of the epidermal differentiation complex (EDC), within chromosomal band 1q21, while the mouse gene maps within the mouse EDC, on mouse chromosome 3, between S100A9 and S100A13. The structure of the human gene has been determined, and message was detected in most adult and fetal tissues including the epidermis. The mouse gene is developmentally regulated and found expressed in fetal and adult suprabasal epidermis, osteoblasts, small intestine, and salivary gland.
Subject(s)
Carrier Proteins/isolation & purification , Cation Transport Proteins , Epidermal Cells , Epidermis/metabolism , Multigene Family , Sequence Homology, Amino Acid , Adult , Amino Acid Sequence , Animals , Base Sequence , Blotting, Northern , Carrier Proteins/biosynthesis , Carrier Proteins/chemistry , Carrier Proteins/genetics , Cell Differentiation/genetics , Chromosomes, Human, Pair 1/genetics , Cloning, Molecular , DNA, Complementary/chemistry , DNA, Complementary/isolation & purification , Exons , Gene Expression Regulation, Developmental , Humans , In Situ Hybridization , Introns , Iron/metabolism , Mice , Molecular Sequence Data , Organ Specificity/genetics , Zinc/metabolismABSTRACT
The human ovalbumin (ov) serpins are associated with tumorigenesis, inflammation, and protection from autolysis by granule proteinases. Their genes are located at 18q21 or 6p25, falling into two structurally very similar but distinct categories depending on the presence or absence of a particular exon. Analysis of ov-serpin gene structure provides an opportunity to elucidate the mechanisms contributing to the formation of the larger serpin gene superfamily. Here we have identified a new gene (PI8L1) at 6p25 that is 72% identical to the 18q21 gene PI8. FISH analysis using the 3' untranslated region of PI8 yielded an additional signal at 18q23, separable from the known 18q21.3 signal by the t(1;18)(p32;q23) chromosomal translocation. The presence of more than one PI8-related gene was confirmed by analysis of human genomic DNA using the same probe. Cloning and analysis of PI8 showed that its intron number and phasing are identical to those of the 6p25 genes PI6, PI9, and ELANH2, and it lacks the interhelical variable loop exon found in other 18q21 genes. PCR analysis demonstrated that PI5 at 18q21 also lacks this exon, indicating that it is organized identically to the 6p25 genes. By contrast, PI10 and megsin have this exon and resemble the other 18q21 genes, PLANH2, SCCA-1, and SCCA-2, in structure. Using these data with an ov-serpin phylogenic tree we have constructed, we propose that the ov-serpin gene clusters arose via interchromosomal duplication of PI5 (or a precursor) to 6p25, followed by duplication at 6p25, and a more recent interchromosomal duplication from 6p25 to 18q to yield PI8.
Subject(s)
Chromosomes, Human, Pair 18/genetics , Chromosomes, Human, Pair 6/genetics , Evolution, Molecular , Serpins/genetics , 3' Untranslated Regions/genetics , Base Sequence , Exons/genetics , Gene Duplication , Genes, Tumor Suppressor , Humans , In Situ Hybridization, Fluorescence , Introns/genetics , Molecular Sequence Data , Multigene Family , Ovalbumin/genetics , Phylogeny , Proteins/genetics , Sequence Homology, Amino Acid , Serine Proteinase Inhibitors/geneticsABSTRACT
Chromosomal band 1q21 contains a number of genes, constituting the Epidermal differentiation complex (EDC), most of which are involved in the process of terminal differentiation of the human epidermis and implicated in several disorders of keratinization and cancer. The physical map of 1q21 has been refined by generating 400 YAC derivatives. These products have allowed us to localize EDC genes and additional ESTs precisely. The transcriptional map of the region has been extended by positioning 20 ESTs reported to map between D1S442 and D1S305. Eight of the ESTs are localized in two distinct clusters, confirmed by isolating PACs and chromosome 1-specific cosmids. Two of the ESTs correspond to the genes for YL1 and selenium-binding protein, both of which have potential tumor suppressor activity. Through the use of fragmented YACs and bacterial clones, the order of markers and ESTs in the region has been established as follows: cen-A002O32-Bda44g03-Cda10d12-Bdab5d06, H60056, A005K39-D1S442-WI5663-WI7969-Cx40-Cda0g e12-Cda0kh05-A002D26- A008S07-Cda0ff08-D1S498-S100A10-WI7815( THH)-WI7217(FLG)-D1S1664-INV-SPRR2A- LOR-A001X21-D1S305-tel.
