Conserved elements within first intron of aquaporin-5 (Aqp5) function as transcriptional enhancers.
A 4.3 kb rat aquaporin-5 (Aqp5) promoter that directs lung and salivary cell-specific expression in vitro directs low level expression of a GFP reporter in lungs of transgenic mice. Alignment of rat, mouse, and human AQP5 genomic sequences identified a highly conserved region in the 3' portion of intron 1, here termed ci1. To investigate the role of ci1 in Aqp5 expression, transient transfections were undertaken in AQP5-expressing mouse lung epithelial (MLE-15) and rat salivary (Pa-4) cells and AQP5-non-expressing NIH/3T3 cells. A 536 bp ci1 fragment enhanced transcriptional activity of the rat Aqp5 minimal promoter specifically in MLE-15 cells in an orientation-independent manner. Enhancer activity was Aqp5 promoter-specific, since no increase in activity was detected with the TK promoter. These results suggest that expression of transgenes in mouse lungs under direction of the 4.3 kb rat Aqp5 promoter may be augmented by inclusion of ci1 in transgenic constructs.
Flodby
Per
P
Will Rogers Institute Pulmonary Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA. flodby@uc.edu
Zhou
Beiyun
B
Ann
David K
DK
Kim
Kwang-Jin
KJ
Minoo
Parviz
P
Crandall
Edward D
ED
Borok
Zea
Z
D000818:Animals; D051402:Aquaporin 5 / Q000235:genetics*; D002460:Cell Line; D004742:Enhancer Elements, Genetic; D007438:Introns / Q000235:genetics*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D011401:Promoter Regions, Genetic; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*; D014162:Transfection
D051402:Aquaporin 5; D011993:Recombinant Fusion Proteins; D008156:Luciferases