Analysis of an alternative promoter that regulates tissue-specific expression of the human aromatic L-amino acid decarboxylase gene in cultured cell lines

1996 ◽  
Vol 103 (1-2) ◽  
pp. 1-15 ◽  
Author(s):  
C. Sumi-Ichinose ◽  
S. Hasegawa ◽  
M. Ohtsuki ◽  
H. Nomura ◽  
T. Nomura ◽  
...  
2002 ◽  
Vol 64 (2) ◽  
pp. 514-524 ◽  
Author(s):  
Chiho Sumi-Ichinose ◽  
Seiko Hasegawa ◽  
Hiroshi Ichinose ◽  
Hirohide Sawada ◽  
Kazuto Kobayashi ◽  
...  

2000 ◽  
Vol 20 (9) ◽  
pp. 3316-3329 ◽  
Author(s):  
Carsten Müller ◽  
Carol Readhead ◽  
Sven Diederichs ◽  
Gregory Idos ◽  
Rong Yang ◽  
...  

ABSTRACT Gene expression in mammalian organisms is regulated at multiple levels, including DNA accessibility for transcription factors and chromatin structure. Methylation of CpG dinucleotides is thought to be involved in imprinting and in the pathogenesis of cancer. However, the relevance of methylation for directing tissue-specific gene expression is highly controversial. The cyclin A1 gene is expressed in very few tissues, with high levels restricted to spermatogenesis and leukemic blasts. Here, we show that methylation of the CpG island of the human cyclin A1 promoter was correlated with nonexpression in cell lines, and the methyl-CpG binding protein MeCP2 suppressed transcription from the methylated cyclin A1 promoter. Repression could be relieved by trichostatin A. Silencing of a cyclin A1 promoter-enhanced green fluorescent protein (EGFP) transgene in stable transfected MG63 osteosarcoma cells was also closely associated with de novo promoter methylation. Cyclin A1 could be strongly induced in nonexpressing cell lines by trichostatin A but not by 5-aza-cytidine. The cyclin A1 promoter-EGFP construct directed tissue-specific expression in male germ cells of transgenic mice. Expression in the testes of these mice was independent of promoter methylation, and even strong promoter methylation did not suppress promoter activity. MeCP2 expression was notably absent in EGFP-expressing cells. Transcription from the transgenic cyclin A1 promoter was repressed in most organs outside the testis, even when the promoter was not methylated. These data show the association of methylation with silencing of the cyclin A1 gene in cancer cell lines. However, appropriate tissue-specific repression of the cyclin A1 promoter occurs independently of CpG methylation.


2007 ◽  
Vol 32 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Shelley X. L. Zhang ◽  
Tina R. Searcy ◽  
Yiman Wu ◽  
David Gozal ◽  
Yang Wang

Expression patterns of monocarboxylate transporter 2 (MCT2) display mRNA diversity in a tissue-specific fashion. We cloned and characterized multiple mct2 5′-cDNA ends from the mouse and determined the structural organization of the mct2 gene. We found that transcription of this gene was initiated from five independent genomic regions that spanned >80 kb on chromosome 10, resulting in five unique exon 1 variants (exons 1a, 1b, 1c, 1d, and 1e) that were then spliced to the common exon 2. Alternative splicing of four internal exons (exons AS1, AS2, AS3, and exon 3) greatly increased the complexity of mRNA diversity. While exon 1c was relatively commonly used for transcription initiation in various tissues, other exon 1 variants were used in a tissue-specific fashion, especially exons 1b and 1d that were used exclusively for testis-specific expression. Sequence analysis of 5′-flanking regions upstream of exons 1a, 1b, and 1c revealed the presence of numerous potential binding sites for ubiquitous transcription factors in all three regions and for transcription factors implicated in testis-specific or hypoxia-induced gene expression in the 1b region. Transient transfection assays demonstrated that each of the three regions contained a functional promoter and that the in vitro, cell type-specific activities of these promoters were consistent with the tissue-specific expression pattern of the mct2 gene in vivo. These results indicate that tissue-specific expression of the mct2 gene is controlled by multiple alternative promoters and that both alternative promoter usage and alternative splicing contribute to the remarkable mRNA diversity of the gene.


Author(s):  
Martine Gestin ◽  
Isabelle Le Huërou-Luron ◽  
Catherine Wicker-Planquart ◽  
Gwenola Le Dréan ◽  
Jean-Claude Chaix ◽  
...  

2010 ◽  
Vol 299 (2) ◽  
pp. C251-C263 ◽  
Author(s):  
Christian Barmeyer ◽  
Christoph Rahner ◽  
Youshan Yang ◽  
Frederick J. Sigworth ◽  
Henry J. Binder ◽  
...  

KCNN4 channels that provide the driving force for cAMP- and Ca2+-induced anion secretion are present in both apical and basolateral membranes of the mammalian colon. However, only a single KCNN4 has been cloned. This study was initiated to identify whether both apical and basolateral KCNN4 channels are encoded by the same or different isoforms. Reverse transcriptase-PCR (RT-PCR), real-time quantitative-PCR (RT-QPCR), and immunofluorescence studies were used to clone and identify tissue-specific expression of KCNN4 isoforms. Three distinct KCNN4 cDNAs that are designated as KCNN4a, KCNN4b, and KCNN4c encoding 425, 424, and 395 amino acid proteins, respectively, were isolated from the rat colon. KCNN4a differs from KCNN4b at both the nucleotide and the amino acid level with distinct 628 bp at the 3′-untranslated region and an additional glutamine at position 415, respectively. KCNN4c differs from KCNN4b by lacking the second exon that encodes a 29 amino acid motif. KCNN4a and KCNN4b/c are identified as smooth muscle- and epithelial cell-specific transcripts, respectively. KCNN4b and KCNN4c transcripts likely encode basolateral (40 kDa) and apical (37 kDa) membrane proteins in the distal colon, respectively. KCNN4c, which lacks the S2 transmembrane segment, requires coexpression of a large conductance K+ channel β-subunit for plasma membrane expression. The KCNN4 channel blocker TRAM-34 inhibits KCNN4b- and KCNN4c-mediated 86Rb (K+ surrogate) efflux with an apparent inhibitory constant of 0.6 ± 0.1 and 7.8 ± 0.4 μM, respectively. We conclude that apical and basolateral KCNN4 K+ channels that regulate K+ and anion secretion are encoded by distinct isoforms in colonic epithelial cells.


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1519
Author(s):  
Rowshon A. Begam ◽  
Jayne D’Entremont ◽  
Allen Good

The Arabidopsis L-type Amino Acid Transporter-5 (LAT5; At3g19553) was recently studied for its role in developmental responses such as flowering and senescence, under an assumption that it is a polyamine uptake transporter (PUT5). The LATs in Arabidopsis have a wide range of substrates, including amino acids and polyamines. This report extensively studied the organ and tissue-specific expression of the LAT5/PUT5 and investigated its role in mediating amino acid transport. Organ-specific quantitative RT-PCR detected LAT5/PUT5 transcripts in all organs with a relatively higher abundance in the leaves. Tissue-specific expression analysis identified GUS activity in the phloem under the LAT5/PUT5 promoter. In silico analysis identified both amino acid transporter and antiporter domains conserved in the LAT5/PUT5 protein. The physiological role of the LAT5/PUT5 was studied through analyzing a mutant line, lat5-1, under various growth conditions. The mutant lat5-1 seedlings showed increased sensitivity to exogenous leucine in Murashige and Skoog growth medium. In soil, the lat5-1 showed reduced leaf growth and altered nitrogen content in the seeds. In planta radio-labelled leucine uptake studies showed increased accumulation of leucine in the lat5-1 plants compared to the wild type when treated in the dark prior to the isotopic feeding. These studies suggest that LAT5/PUT5 plays a role in mediating amino acid transport.


1994 ◽  
Vol 64 ◽  
pp. 142
Author(s):  
Chiho Sumi-Ichinose ◽  
Seiko Hasegawa ◽  
Hiroshi Ichinose ◽  
Hirohide Sawada ◽  
Kazuto Kobayashi ◽  
...  

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