Positive transcriptional regulatory element located within exon 1 of elastin gene

Abstract

-Elastin gene transcription is cell type specific and developmentally regulated, but the promoter often exhibits relatively weak activity in transient transfections of cells that express elastin at high levels. To search for positive-acting regulatory sequences, we isolated genomic clones spanning the mouse elastin gene and extensive 5Ј-and 3Ј-flanking regions. Restriction fragments of potential regulatory regions were ligated 5Ј or 3Ј relative to the active promoter to test for enhancer activity in transient transfections of fetal rat lung fibroblasts, which express elastin at high levels, and distal lung epithelial cells, which do not express detectable elastin. Fragments of intron 1 did not exhibit significant enhancer activity. Inclusion of the 84-bp exon 1 and adjacent 5Ј-untranslated region increased activity of the elastin promoter approximately sixfold compared with parental constructs. Transfections with constructs of varying promoter length showed that as little as 40 bp of the 5Ј end of exon 1 confers enhanced activity in elastin-expressing rat lung fibroblasts, but these constructs had variable activity in lung epithelial cell lines. This region, localized between the transcription start site and extending into exon 1, binds Sp1 in nuclear extracts from elastinexpressing cells. These studies indicate a role for the 5Ј end of the first exon of the elastin gene in regulating strong transcriptional activity in elastogenic cells.promoter; lung ELASTIN IS AN ABUNDANT PROTEIN in connective tissues, comprising as much as 35% of the dry weight of the adult human thoracic aorta. Expression of the elastin (ELN) gene coincides with the formation of tissues such as blood vessels and the lung during development and peaks during morphological maturation of these tissues. Lung ELN gene expression is limited to airway and vascular smooth muscle cells, vascular endothelial cells, pleural mesothelial cells, and alveolar myofibroblasts and increases Ͼ10-fold between early stages of lung development and the postnatal alveolarization period (19,30). Elastin expression is undetectable in lung epithelial cells. Analyses of the elastin 5Ј-flanking region from Ϫ6 kb to the translation start site have defined a number of responsive elements, both positive and negative, but none that confers high, cell typespecific activity in transient transfections of cultured elastinexpressing cell types including neonatal lung myofibroblasts, fetal aortic smooth muscle cells, and fetal auricular chondrocytes. In transient transfection studies using cells that express both elastin and type I collagen at relatively similar levels, for example, ELN promoter constructs exhibit weak activity compared with type I collagen promoter constructs (7). Moreover, early studies using ELN promoter constructs showed approximately equivalent activity in elastogenic and nonelastogenic cells in transient transfections. Fazio and coworkers (7) found that a construct extending from Ϫ475 to Ϫ14 exhibited nearly as high activity in HT-1080 cells, which do not ex...

Identification of aCis-Acting Regulatory Polymorphism in a EucalyptCOBRA-Like Gene Affecting Cellulose Content

“…Regulatory elements such as transcriptional enhancers and silencers are generally found in noncoding sequences such as promoters, introns, and untranslated regions. However, there are a few reports of the occurrence of transcriptional regulatory elements in coding regions (Neznanov et al 1997;Lang et al 2005;Pierce et al 2006). Barthel and Liu (2008) used computational approaches to identify a transcriptional regulatory element in exon 2 of ADAMTS5, a human myogenesis gene.…”

Applications of solid state NMR to cardiolipin and elastin.

“…In the context of robustness, it is noteworthy that the majority of elastin in mammals is formed during the development and post-natal growth. In mature organisms, the production ceases and only occurs in response to injury [50][51].…”

“…To experimentally determine the relative importance of these two mechanisms in the function of elastin, we measure changes in ordering of the backbone, using 13e NMR, and the solvent, using 2H MQ NMR, as a function of stretch, hydration and temperature. These studies are fundamental for the design of biocompatible elastomeric materials for wound repair, construction of artificial blood vessels [51] and other applications of elastin in tissue engineering. The involvement of anionic phospholipids in proton conduction in the membranes of energy producing organelles was hypothesized in the early 1980's [70].…”

The role of Nfix in the development of the embryonic and postnatal cerebral cortex

“…Although not common, transcription factor-binding sites have been identified in silico within the exonic region of many genes (Gotea et al 2012). Moreover, the first exon of the elastin gene has been shown to possess a regulatory element that facilitates the expression of this gene (Pierce et al 2006), while the transcription factor GATA-1 binds to a regulatory region in exon 1 of the C-C chemokine receptor type 3 mice were also generated within DAVID. Solute carrier family 25 (mitochondrial carrier, adenine nucleotide translocator); solute carrier family 6 (neurotransmitter transporter, GABA), member 1; solute carrier family 6 (neurotransmitter transporter, GABA), member 11; synaptotagmin I Integrin-mediated signaling pathway…”