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1.
Structure and expression of the human apolipoprotein A-IV gene 总被引:8,自引:0,他引:8
N A Elshourbagy D W Walker Y K Paik M S Boguski M Freeman J I Gordon J M Taylor 《The Journal of biological chemistry》1987,262(17):7973-7981
2.
Rat liver contains two class 1 aldehyde dehydrogenases (ALDHs): a constitutive isozyme (ALDH1) and a phenobarbital-inducible isozyme (ALDH-PB). Defining characteristics of mammalian class 1 ALDHs include a homotetrameric structure, high expression in liver, sensitivity to the inhibitor disulfiram, and high activity for the oxidation of retinal. It is often presumed that ALDH-PB is the rat ortholog of mammalian ALDH1, and the identity of rat ALDH-PB is commonly interchanged with ALDH1. In this study, we characterized recombinant rat liver cytosolic ALDH1 and ALDH-PB. Previous reports indicate that ALDH-PB is a homodimer; however, we found by mass spectrometry and gel electrophoresis that it is a homotetramer. ALDH1 mRNA was highly expressed in untreated rat liver, while ALDH-PB had very weak expression, in contrast to a previous report that ALDH-PB mRNA is expressed in untreated rat liver. Rat liver ALDH1 had a high affinity for retinal (K(m) = 0.6 microM), while no oxidation by ALDH-PB could be detected with 20 microM retinal. ALDH1 was more efficient at oxidizing acetaldehyde, propionaldehyde, and benzaldehyde and was more sensitive to disulfiram inhibition. We conclude that rat liver ALDH1 is the ortholog of mammalian liver ALDH1. Furthermore, despite a high level of sequence identity and classification as a class 1 ALDH, ALDH-PB does not function like ALDH1. ALDH-PB is not merely an inducible ALDH1 isozyme; it is a distinct ALDH isozyme. 相似文献
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Heavy metal-mediated activation of the rat Cu/Zn superoxide dismutase gene via a metal-responsive element 总被引:5,自引:0,他引:5
The Cu/Zn superoxide dismutase (SOD1) catalyzes the dismutation of superoxide radicals produced in the course of biological
oxidations. When placed under the control of the rat SOD1 gene promoter and transfected into human HepG2 hepatoma cells, the activity of a chloramphenicol acetyltransferase reporter
gene was found to increase three- to four-fold in the presence of heavy metals (cadmium, zinc and copper). Functional analysis
of mutant derivatives of the SOD1 gene promoter and the use of a heterologous promoter system confirmed that the induction of the SOD1 gene by metal ions requires a metal-responsive element (MRE) located between positions −273 and −267 (GCGCGCA). It was also
shown by gel mobility shift assays that an MRE binding protein is induced by the exposure of the human liver cell line HepG2
to heavy metals. These results suggest that the MRE participates in the induction of the SOD1 gene by heavy metals.
Received: 5 February 1999 / Accepted: 21 May 1999 相似文献
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An ORF of 1716 nucleotides, putatively encoding a DNA polymerase, was characterized in the mitochondrial genome of the edible
basidiomycete Agrocybe aegerita. The complete gene, named Aa-polB, and its flanking regions were cloned and sequenced from three overlapping restriction fragments. Aa-polB is located between the SSU rDNA (5′ region) and a gene for tRNAAsn (3′ region), and is separated from these genes by two A+T-rich intergenic regions of 1048 (5′ region) and 3864 (3′ region)
nucleotides, which lack repeated sequences of mitochondrial or plasmid origin. The deduced Aa-POLB protein shows extensive
sequence similarity with the family B DNA polymerases encoded by genomes that rely on protein-primed replication (invertrons).
The domains involved in the 3′→5′ exonuclease (Exo I to III) and polymerase (Pol I to Pol V) activities were localized on
the basis of conserved sequence motifs. The alignment of the Aa-POLB protein (571 amino acids) with sequences of family B
DNA polymerases from invertrons revealed that in Aa-POLB the N-terminal region preceding Exo I is short, suggesting a close
relationship with the DNA polymerases of bacteriophages that have linear DNA. The Aa-polB gene was shown to be present in all wild strains examined, which were collected from a wide range of locations in Europe.
As shown by RT-PCR, the Aa-polB gene is transcribed in the mitochondria, at a low but significant level. The likelihood of the coexistence of Aa-POLB and
Pol γ in the A. aegerita mitochondrion is discussed in the light of recent reports showing the conservation of the nucleus-encoded Pol γ from yeast
to human.
Received: 13 October 1998 / Accepted: 21 December 1998 相似文献
7.
Yunfei Chen Hyun S. Lillehoj Chung-Hsin Hsu Susan L. Carpenter S. J. Lamont 《Immunogenetics》1997,45(4):242-248
A 0.7 kilobase (kb) DNA fragment from the 5′ flanking region of a chicken major histocompatibility complex (MHC) class II B gene was cloned into chloramphenicol acetyltransferase (CAT) reporter vectors and was transfected into a chicken macrophage
cell line that expresses a low level of MHC class II antigens. Positive orientation-dependent promoter activity of the chicken
DNA was evident in a reporter construct containing an SV40 enhancer. Deletion analysis of this 0.7 kb DNA fragment revealed
a short fragment in the 3′ end that was crucial for the promoter function and negative regulatory elements (NRE) located further upstream. The conserved MHC class II X and Y boxes did not have a significant effect on promoter activity. Sequence analysis of the 0.7 kb class II B gene upstream region suggests possible involvement of interferon (IFN), E twenty-six specific (ETS)-related proteins, and
other factors in regulating this promoter. A chicken T-cell line culture supernatant increased surface expression of MHC class
II antigens, as well as class II promoter activity, in this macrophage cell line. This first functional characterization of
a chicken MHC class II B gene promoter will aid in understanding the regulatory mechanisms that control the expression of these genes.
Received: 9 July 1996 / Revised: 7 October 1996 相似文献
8.
We have characterized the promoter specificity of theArabidopsis thaliana α1-tubulin (α
1-tub) gene by studying expression patterns of gene fusions between the 2.2 kbp 5′ upstream region of theα
1-tub gene and each of three different reporters: chloramphenical acetyltransferase, β-glucuronidase or the diphtheria toxin chain
A gene. Analysis of transgenic tobacco andArabidopsis plants carrying the transgene showed that the chloramphenicol acetyltransferase and β-glucuronidase activities were not detected
in any vegetative or reproductive organs except mature pollen. Transgenic tobacco plants carrying the diphtheria toxin chain
A gene under the control of theα
1-tub promoter were of normal phenotype but seed fertility was drastically reduced. Furthermore, the transgene could not be transmitted
to the next generation through pollen, supporting the observation that theα
1-tub promoter is active only in pollen. It was observed that the promoter activity was most active in mature pollen and decreased
significantly duringin vitro pollen germination, indicating that the promoter is inactive or subdued in germinating pollen. The promoter activity was
not affected by various plant growth hormones during pollen maturation. 相似文献
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Mini-exon derived RNA is a small nuclear RNA of trypanosomatid protozoa such asLeishmania which donates its 5′-terminal 39 nucleotides to the 5’-ends of cellular messenger RNAs by trans-splicing. We have cloned
a mini-exon derived RNA gene fromLeishmania donovani and studied its organization and expression. About 200 copies of the gene per haploid genome are organized as a tandem repeat
on a single chromosome. The gene is transcribed as a 95-nucleotide RNA. The first 39 nucleotides of mini-exon derived RNA
is also found at the 5′-terminus of a cellular mRNA (Β-tubulin), thus confirming its identity. Sequence analysis of the gene
and its flanking regions showed that while classical RNA polymerase II promoter elements such as TATA and CAAT are absent
from the 5′-upstream region, intragenic sequence motifs resembling RNA polymerase III promoter elements are present. The implications
of this finding for mini-exon derived RNA expression are discussed. 相似文献
11.
Imma Ponte Claudio Monsalves Miguel Cabañas Pedro Martínez Pedro Suau 《Journal of molecular evolution》1996,43(2):125-134
The H1° gene has a long 3′ untranslated region (3′UTR) of 1,125 nucleotides in the rat and 1,310 in humans. Analysis of the
sequences shows that they have features of simple DNA that suggest involvement of replication slippage in their evolution.
These features include the length imbalance between the rat and human sequences; the abundance of single-base repeats, two-base
runs and other simple motifs clustered along the sequence; and the presence of single-base repeat length polymorphisms in
the rat and mouse sequences. Pairwise comparisons show numerous short insertions/deletions, often flanked by direct repeats.
In addition, a proportion of short insertions/deletions results from length differences in conserved single-base repeats.
Quantification of the sequence simplicity shows that simple sequences have been more actively incorporated in the human lineage
than in the rodent lineage. The combination of insertions/deletions and nucleotide substitutions along the sequence gives
rise to three main regions of homology: a highly variable central region flanked by more conserved regions nearest the coding
region and the polyA addition site.
Correspondence to: P. Suau 相似文献
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WU Naihu FANG Xiaohua SHI Xiaomei ZHANG Xiaowu ZHOU Li HUANG Meijuan 《中国科学:生命科学英文版》1999,42(4):383-394
Comparative analysis reveals remarkahle homology between the sequences of bothpsbA gene nucleotides and the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5′-noncoding region of sorghumpsbA gene contains the conservative promoter elements, “—35” element and “—10” element, like the prokaryote and the promoter element,
TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence
of the mRNA in the former. Using anin vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically hinds
to the 5′-noncoding region ofpsbA gene. Measurement of the expression of luciferase shows a 2–5 time greater reaction of the expression plasmids pALqs which
contain leader region of sorghumpsbA gene than that of the expression plasmids pALqr which contain leader region of ricepsbA gene inE. coli.
Project supported by the Chinese National “863” and “973” Projects 相似文献
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Structural feature of sorghum chloroplastpsbA gene and regulation effects of its 5′-noncoding region
Naihu Wu Xiaohua Fang Xiaomei Shi Xiaowu Zhang Li Zhou Meijuan Huang 《中国科学C辑(英文版)》1999,42(4):383-394
Comparative analysis reveals remarkahle homology between the sequences of bothpsbA gene nucleotides and the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5′-noncoding region of sorghumpsbA gene contains the conservative promoter elements, “—35” element and “—10” element, like the prokaryote and the promoter element, TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence of the mRNA in the former. Using anin vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically hinds to the 5′-noncoding region ofpsbA gene. Measurement of the expression of luciferase shows a 2–5 time greater reaction of the expression plasmids pALqs which contain leader region of sorghumpsbA gene than that of the expression plasmids pALqr which contain leader region of ricepsbA gene inE. coli. 相似文献
18.
Tracey M. Reed James E. Browning Ruthann I. Blough Charles V. Vorhees David R. Repaske 《Mammalian genome》1998,9(7):571-576
Cyclic nucleotide phosphodiesterases (PDEs) catalyze the hydrolysis of cAMP and cGMP, thereby participating in regulation
of the intracellular concentrations of these second messengers. The PDE1 family is defined by regulation of activity by calcium
and calmodulin. We have cloned and characterized the mouse PDE1B gene, which encodes the 63-kDa calcium/calmodulin-dependent PDE (CaM-PDE), an isozyme that is expressed in the CNS in the
olfactory tract, dentate gyrus, and striatum and may participate in learning, memory, and regulation of phosphorylation of
DARPP-32 in dopaminergic neurons. We screened an I-129/SvJ mouse genomic library and identified exons 2–13 of the PDE1B gene that span 8.4 kb of genomic DNA. Exons range from 67 to 205 nucleotides and introns from 91 to 2250 nucleotides in length.
Exon 1 was not present in the 3 kb of genomic DNA 5′ to exon 2 in our clones. The mouse PDE1B gene shares many similar or identical exon boundaries as well as considerable sequence identity with the rat PDE4B and PDE4D genes and the Drosophila dunce cAMP-specific PDE gene dnc, suggesting that these genes all arose from a common ancestor. Using fluorescence in situ hybridization, we localized the
PDE1B gene to the distal tip of mouse Chromosome (Chr) 15.
Received: 10 November 1997 / Accepted: 12 March 1998 相似文献
19.
Genes for two forms of human placenta diamine oxidase(dao) were cloned from a cDNA library and sequenced. One gene,pdao 1, is identical in length to human kidneydao but differs from it by two bases in the coding region and differs slightly in the 3′- and 5′-noncoding regions. The second
gene,pdao2, is nearly identical to these genes in the coding region, except that it has an extra 57-nucleotide coding segment near the
3′ end of this region. This segment corresponds to the contiguous sequence of the 3′ end of intron 3 of human kidneydao. pdao2 also differs significantly frompdao1 and human kidneydao in a 13-base sequence in the 5′-noncoding region. It is proposed thatpdao1 and human kidneydao are polymorphic forms of the same allele. Whetherpdao2 is a polymorph of these two is not certain, because of the significant differences in the coding and noncoding regions.Pdao2 may represent a different allele.
This work was supported by a Department of Veterans Affairs Merit Review Grant, Program Project Grant HL 16251 from the Heart,
Lung and Blood Institute of the NIH, and an Academic Senate Grant from the University of California, San Francisco. 相似文献