Tissue-specific regulation of the mouse Pkhd1 (ARPKD) gene promoter

Autosomal recessive polycystic kidney disease, an inherited disorder characterized by the formation of cysts in renal collecting ducts and biliary dysgenesis, is caused by mutations of the polycystic kidney and hepatic disease 1 ( PKHD1) gene. Expression of PKHD1 is tissue specific and developmentally regulated. Here, we show that a 2.0-kb genomic fragment containing the proximal promoter of mouse Pkhd1 directs tissue-specific expression of a lacZ reporter gene in transgenic mice. LacZ is expressed in renal collecting ducts beginning during embryonic development but is not expressed in extrarenal tissues. The Pkhd1 promoter contains a binding site for the transcription factor hepatocyte nuclear factor (HNF)-1β, which is required for activity in transfected cells. Mutation of the HNF-1β-binding site abolishes the expression of the lacZ reporter gene in renal collecting ducts. Transgenes containing the 2.0-kb promoter and 2.7 kb of additional genomic sequence extending downstream to the second exon are expressed in the kidney, intrahepatic bile ducts, and male reproductive tract. This pattern overlaps with the endogenous expression of Pkhd1 and coincides with sites of expression of HNF-1β. We conclude that the proximal 2.0-kb promoter is sufficient for tissue-specific expression of Pkhd1 in renal collecting ducts in vivo and that HNF-1β is required for Pkhd1 promoter activity in collecting ducts. Additional genomic sequences located from exons 1-2 or elsewhere in the gene locus are required for expression in extrarenal tissues.

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The suppressor of Hairy-wing protein regulates the tissue-specific expression of the Drosophila gypsy retrotransposon.

Genetics ◽

10.1093/genetics/139.1.215 ◽

1995 ◽

Vol 139 (1) ◽

pp. 215-228 ◽

Cited By ~ 2

Author(s):

P A Smith ◽

V G Corces

Keyword(s):

Reporter Gene ◽

Leucine Zipper ◽

Fat Body ◽

Lacz Reporter ◽

Lacz Expression ◽

Lacz Reporter Gene ◽

Specific Expression ◽

Tissue Specific ◽

Gypsy Retrotransposon ◽

Beta Galactosidase

Abstract The gypsy retrotransposon of Drosophila melanogaster causes mutations that show temporal and tissue-specific phenotypes. These mutant phenotypes can be reversed by mutations in su(Hw), a gene that also regulates the transcription of the gypsy element. Gypsy encodes a full-length 7.0-kb RNA that is expressed in the salivary gland precursors and fat body of the embryo, imaginal discs and fat body of larvae, and fat body and ovaries of adult females. The su(Hw)-binding region inserted upstream of the promoter of a lacZ reporter gene can induce beta-galactosidase expression in a subset of the embryonic and larval tissues where gypsy is normally transcribed. This expression is dependent on the presence of a functional su(Hw) product, suggesting that this protein is a positive activator of gypsy transcription. Flies transformed with a construct in which the 5' LTR and leader sequences of gypsy are fused to lacZ show beta-galactosidase expression in all tissues where gypsy is normally expressed, indicating that sequences other than the su(Hw)-binding site are required for proper spatial and temporal expression of gypsy. Mutations in the zinc fingers of su(Hw) affect its ability to bind DNA and to induce transcription of the lacZ reporter gene. Two other structural domains of su(Hw) also play an important role in transcriptional regulation of gypsy. Deletion of the amino-terminal acidic domain results in the loss of lacZ expression in larval fat body and adult ovaries, whereas mutations in the leucine zipper region result in an increase of lacZ expression in larval fat body and a decrease in adult ovaries. These effects might be the result of interactions of su(Hw) with activator and repressor proteins through the acidic and leucine zipper domains to produce the final pattern of tissue-specific expression of gypsy.

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