Human proteinase-3 is one of three serine proteinases present in the azurophil granules of polymorphonuclear leukocytes along with elastase and cathepsin G. Proteinase-3 gene expression is confined to the promyelocytic stage of polymorphonuclear leukocyte maturation. The present investigation identifies elements responsible for this highly controlled tissue-and developmental-specific expression of proteinase-3. Within the first 200 base pairs of the proteinase-3 promoter, two elements were identified as important for expression, these elements at ؊101 and ؊190 confer the majority of the activity. The element at ؊101 has a PU.1 consensus. It binds a myeloid nuclear protein of approximately 45 kDa that "supershifts" with PU.1 antibody and is competed by the CD11b PU.1 element. The element at ؊190 has a core sequence of CCCCGCCC (CG element). The cytidines but not the guanidine are essential for promoter activity. The CG element binds a second nuclear protein with a molecular mass of approximately 40 kDa that is found in cells of myeloid lineage as well as non-myeloid HeLa cells. However, the proteinase-3 promoter is not active in HeLa cells which suggests that the CG element alone is not sufficient for proteinase-3 gene expression. Maturation of promyelocytic cells results in an inhibition of proteinase-3 gene expression and a reduction in nuclear protein binding to the PU.1 and CG elements. Similar elements occur in the elastase and cathepsin G promoters. Using the elastase and cathepsin G PU.1 and CG-like elements as probes results in identical band-shift patterns to that obtained with proteinase-3 PU.1 and CG elements. These data suggest that there is cooperative interaction between a PU.1 and a CG element with a consensus of CCCCXCCC and that they are important control elements for tissue-and developmental-specific expression of azurophil serine proteinases of polymorphonuclear leukocytes.

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Uroporphyrinogen decarboxylase (URO-D) is a cytosolic heme-biosynthetic enzyme that converts uroporphyrinogen to coproporphyrinogen. Defects at the uroporphyrinogen decarboxylase locus cause the human genetic disease familial porphyria cutanea tarda. A splice site mutation has been found in a pedigree with familial porphyria cutanea tarda that causes exon 6 to be deleted from the mRNA. The intron/exon junctions on either side of exon 6 fall between codons, so the resulting protein is shorter than the normal protein, missing only the amino acids coded by exon 6. The shortened protein lacks catalytic activity, is rapidly degraded when exposed to human lymphocyte lysates, and is not detectable by Western blot analysis in lymphocyte lysates derived from affected individuals. The mutation was detected in five of 22 unrelated familial porphyria cutanea tarda pedigrees tested, so it appears to be common. This is the first splice site mutation to be found at the URO-D locus, and the first mutation that causes familial porphyria cutanea tarda to be found in more than one pedigree. (J.

Proteinase-3 (PR-3) and neutrophil elastase (NE) are polymorphonuclear leukocyte serine proteinases that degrade extracellular matrix proteins including elastin and appear to be involved in the pathogenesis of several diseases characterized by tissue destruction most notably emphysema and Wegener’s granulomatosis. In this report we characterize and compare the mouse PR-3 and NE genes and establish by FISH analysis a common location on mouse chromosome 10C2. Each gene consists of five exons and four introns conserving the typical granule-associated serine proteinase gene structure. The mouse PR-3 gene (Prtn3) is approximately 3.7 kb and is within 2.2 kb of the smaller (1.7 kb) NE gene (Ela2). The larger size of Prtn3 is accounted for by differences in intron sizes. A comparison between the mouse and human PR-3 cDNA reveals 73% homology, however, this drops to 60% when the amino acid sequences are compared. Homology between the mouse and human NE cDNA is 77% for both the cDNA and amino acid sequences. The catalytic triad and its placement are conserved among the four genes. The proximal promoter of mouse Prtn3 contains a TATA box, c-myb and an ets transcriptional site. As these are functional elements in the mouse Ela2 promoter they may also be important in the expression of Prtn3.

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