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At least 109 records · Page 6Linked to original sources
PubMed1990

The stimulation of uterine complement component C3 gene expression by antiestrogens.

We have previously demonstrated that complement component C3 is regulated by estradiol in the rat uterus. The antiestrogens tamoxifen, LY117018, and LY156758 exert both agonist and antagonist effects on the immature rat uterus. In this study, these three antiestrogens also stimulated an increase in the synthesis and secretion of C3. The combination of LY117018 and estradiol did not increase C3 to a greater extent than LY117018 alone, which suggests a similar mechanism of regulation. The regulation may be transcriptional since both estradiol and tamoxifen increase the concentration of C3 mRNA. Results of in situ hybridization revealed that the increase in C3 mRNA occurred in the luminal epithelial cells. Although the induction by estradiol and the antiestrogens was similar in most aspects, the time course for tamoxifen-stimulated synthesis differed from estradiol in that the time required to achieve maximal concentrations of C3 was delayed by 12 h with tamoxifen. This pattern did not appear to be related to the time it took to convert tamoxifen to 4-hydroxytamoxifen since the C3 response for these antiestrogens were identical. The antiestrogen-stimulated increase in C3 synthesis and mRNA concentration was prevented by the co-administration of progesterone lending support to the hypothesis that the antiestrogens regulate C3 synthesis via a mechanism similar to estrogen.

Animals↗
PubMed1993

A positive feedback loop controls transcription of the spoOF gene, a component of the sporulation phosphorelay in Bacillus subtilis.

The spo0F gene of Bacillus subtilis encodes a protein that functions as a secondary messenger in a phosphorelay system controlling the initiation of sporulation. Transcription of the spo0F gene was known to be dependent on an intact gene for the transcription regulator Spo0A. In vitro footprint analysis revealed that Spo0A protein bound to two locations in the spo0F promoter region. Deletion of a 40 bp region upstream of one of the promoters (P2) abolished the activation of spo0F expression that occurs at the onset of stationary phase and sporulation. This 40 bp region contains a Spo0A-binding site. These observations are consistent with a hypothesis that Spo0A binding to this region is responsible for activating spo0F transcription. Additionally, Spo0A binding at a downstream site could modulate the level of this activation. Since Spo0F protein is required for the formation of Spo0A-P (the form needed for transcriptional activation) a positive feedback loop controls transcription of spo0F.

Bacillus subtilis↗
PubMed1993

Conservation of genes encoding components of a type IV pilus assembly/two-step protein export pathway in Neisseria gonorrhoeae.

Three gonococcal genes have been identified which encode proteins with substantial similarities to known components of the type IV pilus biogenesis pathway in Pseudomonas aeruginosa. Two of the genes were identified based on their hybridization with a DNA probe derived from the pilB gene of P. aeruginosa under conditions of reduced stringency. The product of the gonococcal pilF gene is most closely related to the pilus assembly protein PilB of P. aeruginosa while the product of the gonococcal pilT gene is most similar to the PilT protein of P. aeruginosa which is involved in pilus-associated twitching motility and colony morphology. The products of both of these genes display canonical nucleoside triphosphate binding sites and are predicted to be to cytoplasmically localized based on their overall hydrophilicity. The gonococcal pilD gene, identified by virtue of its linkage to the pilF gene, is homologous to a family of prepilin leader peptidase genes. When expressed in Escherichia coli, the gonococcal PilD protein functions to process gonococcal prepilin in a manner consistent with its being gonococcal prepilin peptidase. These results suggest that Neisseria gonorrhoeae is capable of expressing many of the essential elements of a highly conserved protein translocation system and that these gene products are probably involved in pilus biogenesis.

Adenosine Triphosphatases↗
PubMed1984

Demographic components of gene frequency change in free-ranging macaques on Cayo Santiago.

Gene frequency profiles from January 1973 to January 1977 for three polymorphic loci were examined in Cayo Santiago rhesus social groups. The effects of demographic components (i.e., births, deaths, immigrations, emigrations, and group fission and fusion) on total change in gene frequencies are assessed. Allelic frequencies at the carbonic anhydrase II, 6-phosphogluconate dehydrogenase, and transferrin loci were analyzed in four social groups. In the two groups that underwent fission and fusion during the study period, the timing of these processes was related to the largest short-term changes in gene frequences. However, immigration and emigration had the greatest effect on total change in gene frequency in all groups during the study period. The relative importance of births and deaths in producing gene frequency change varied among the social groups. These results suggest that the relative importance of the demographic components of gene frequency change in primate populations is determined by behavioral patterns and ecological conditions specific to the population considered.

Animals↗
PubMed1964

PLASTIDS AND MITOCHONDRIA: INHERITABLE SYSTEMS.

Evidence has been cited which indicates that RNA and DNA are present in plastids and mitochondria. A multigenic apparatus in the plastid is deduced from the properties of bleached Euglena strains. Control mechanisms are present for the differentiation of proplastids to chloroplasts in Euglena and in higher plants, and for the differentiation of promitochondria to mitochondria in yeast. An operon-regulator mechanism for this control is suggested. A comparison of the hereditary cytoplasmic units of Euglena plastids and yeast mitochondria indicates cates great similarities in their properties. Because of these similarities in two unrelated organisms, we suggest that a DNA unit which is self-duplicating and which serves as a code for RNA is the basic hereditary unit of each plastid and mitochondrion. Much work must be done if this reasonable hypothesis is to be converted into well-founded theory. Some pressing problems await solution. We do not understand the nonrandom distribution of plastids in the mitotic divisions of variegated plants. A related unresolved problem is that of maternal inheritance, in which nonrandom segregation of cytoplasmic organelles occurs after fertilization, causing elimination of the organelles which are contributed by the male parent. How different are the gene components of one plastid in a cell from the gene components of other plastids in the same cell, and how do we test for these differences? Can gene exchange or recombination occur between organelles within the same cell? The answers to these questions may have to await development of more sophisticated techniques, such as the ability to transplant these organelles between different cells or to culture cellular organelles in vitro.

Cell Nucleus↗
PubMed2000

Association between obsessive-compulsive disorder and polymorphisms of genes encoding components of the serotonergic and dopaminergic pathways.

Obsessive-compulsive disorder (OCD) is a severe and disabling anxiety disorder with a marked genetic contribution. Pharmacological data indicated involvement of the serotonergic and dopaminergic systems. We studied the association between OCD and six candidate genes encoding important components of the serotonergic and dopaminergic pathways in 75 biologically unrelated patients and 172 ethnically matched controls (Ashkenazi and non-Ashkenazi Jews). Polymorphisms in the following genes were studied: tryptophan hydroxylase (TPH), serotonin 2A receptor (HTR2A), serotonin 2C receptor (HTR2C), serotonin transporter (5-HTT), dopamine receptor D4 (DRD4), and dopamine transporter (DAT1). The genotypic and allelic distribution of all polymorphisms tested did not show statistically significant differences between patients and controls. Our results suggest that these polymorphisms do not play a major role in the genetic predisposition to OCD, although a minor contribution cannot be ruled out.

Carrier Proteins↗
PubMed1994

Mutations in the helper component protease gene of zucchini yellow mosaic virus affect its ability to mediate aphid transmissibility.

The nucleotide sequence of the helper component protease (HC-Pro) genes of three zucchini yellow mosaic virus (ZYMV) strains has been compared with that of a helper-deficient strain of ZYMV-HC. The comparisons revealed three unique deduced amino acid differences. Two of these mutations were located in regions which are conserved in other potyviruses. The role of these mutations in aphid transmissibility was examined by exchanging DNA fragments of part of the deficient HC-Pro gene with the respective section within the gene of the infectious full-length clone of the aphid-transmissible ZYMV. The first exchange included two of the three mutations, the first coding for a change from Asp to Gly (in a non-conserved region) and the second coding for a change from Arg to Ile [within the Phe-Arg-Asp-Lys (FRNK) conserved box]. This exchange resulted in a reduced transmission (20.6% for the mutated virus compared with 57.4% in the normal ZYMV when acquired from plants and 37.2% compared with 83.1%, respectively, when acquired from membranes). The second exchange incorporated a single mutation [conferring a change from Thr to Ala within the Pro-Thr-Lys (PTK) conserved box]. This single mutation resulted in almost total loss of HC activity in aphid transmission both from plants and from membranes. The Lys residue in the conserved Lys-Ile-Thr-Cys (KITC) box, which is related to loss of HC activity in potato virus Y, tobacco vein mottling virus and in the Michigan strain of ZYMV, is unchanged in the helper-deficient ZYMV. It is therefore proposed that more than one site in HC-Pro may be functionally related to aphid transmissibility. The possible reasons for the role of these mutations in helper activity in aphid transmission of ZYMV are discussed.

Amino Acid Sequence↗
PubMed1995

Identification of the hopG gene, a component of Escherichia coli K-12 type II export system, and its conservation among different pathogenic Escherichia coli and Shigella isolates.

The Escherichia coli K-12 gene coding for a component of a type II export system was identified and characterized. The HopG protein contains a typical prepilin peptidase cleavage site and has a high degree of homology with proteins PulG, OutG, and ExeG, which are components of type II secretion systems from Klebsiella pneumoniae, Erwinia carotovora, and Aeromonas hydrophila.

Amino Acid Sequence↗
PubMed2001

The response regulator ARR2: a pollen-specific transcription factor involved in the expression of nuclear genes for components of mitochondrial complex I in Arabidopsis.

Two-component signal systems regulate a variety of cellular activities. They involve at least two common signalling molecules: a signal-sensing kinase and a response regulator that mediates the output response. Multistep systems also require proteins containing phosphotransfer domains. Here we report that the response regulator ARR2 from Arabidopsis is predominantly expressed in pollen and is localized in the nuclear compartment of the plant cell. Furthermore, ARR2 is transcriptionally active in yeast and binds to the promoters of nuclear genes for several components of mitochondrial respiratory chain complex I (nCI) from Arabidopsis. The nuclear nCI genes are up-regulated in pollen during spermatogenesis. The transcription factor functions of ARR2 are mediated by its C-terminal output domain. Our data identify ARR2 as the first eukaryotic response regulator which functions as a transcription factor at a known promoter sequence. Yeast two-hybrid analysis and in vitro interaction studies suggest that ARR2 very probably forms part of a multistep two-component signalling mechanism that includes HPt proteins like AHP1 or AHP2. These findings point to an as yet unidentified signal transduction system that may regulate aspects of floral and mitochondrial gene expression.

Arabidopsis↗
PubMed1993

The Mycobacterium leprae antigen 85 complex gene family: identification of the genes for the 85A, 85C, and related MPT51 proteins.

The genes for two novel members (designated 85A and 85C) of the Mycobacterium leprae antigen 85 complex family of proteins and the gene for the closely related M. leprae MPT51 protein were isolated. The complete DNA sequence of the M. leprae 85C gene and partial sequences of the 85A and MPT51 genes are presented. As in M. tuberculosis, the M. leprae 85A, 85C, and previously identified 85B component genes are not closely linked on the genome. However, the MPT51 genes of both species localize close to the respective 85A component genes. Like the 85B component, the M. leprae 85A-MPT51 and 85C antigens are recognized by T cells from healthy contacts and leprosy patients.

Amino Acid Sequence↗
PubMed2006

Improve survival prediction using principal components of gene expression data.

The purpose of many microarray studies is to find the association between gene expression and sample characteristics such as treatment type or sample phenotype. There has been a surge of efforts developing different methods for delineating the association. Aside from the high dimensionality of microarray data, one well recognized challenge is the fact that genes could be complicatedly inter-related, thus making many statistical methods inappropriate to use directly on the expression data. Multivariate methods such as principal component analysis (PCA) and clustering are often used as a part of the effort to capture the gene correlation, and the derived components or clusters are used to describe the association between gene expression and sample phenotype. We propose a method for patient population dichotomization using maximally selected test statistics in combination with the PCA method, which shows favorable results. The proposed method is compared with a currently well-recognized method.

Algorithms↗
PubMed1994

Genes for components of the chloroplast translational apparatus are conserved in the reduced 73-kb plastid DNA of the nonphotosynthetic euglenoid flagellate Astasia longa.

The colourless, nonphotosynthetic protist Astasia longa is phylogenetically related to Euglena gracilis. The 73-kb plastid DNA (ptDNA) of A. longa is about half the size of most chloroplast DNAs (cpDNAs). More than 38 kb of the Astasia ptDNA sequence has been determined. No genes for photosynthetic function have been found except for rbcL. Identified genes include rpoB, tufA, and genes coding for three rRNAs, 17 tRNAs, and 13 ribosomal proteins. Not only is the nucleotide sequence of these genes highly conserved between A. longa and E. gracilis, but a number of these genes are clustered in a similar fashion and have introns in the same positions in both species. The results further support the idea that photosynthetic genes normally encoded in cpDNA have been preferentially lost in Astasia, but that the chloroplast genes coding for components of the plastid translational apparatus have been maintained. This apparatus might be needed for the expression of rbcL and also for that of still unidentified nonphotosynthetic genes of Astasia ptDNA.

Animals↗
PubMed2004

Metal particulate matter components affect gene expression and beat frequency of neonatal rat ventricular myocytes.

Soluble particulate matter (PM) components (e.g., metals) have the potential to be absorbed into the bloodstream and transported to the heart where they might induce the expression of inflammatory cytokines and remodel electrical properties. We exposed cultured rat ventricular myocytes to similar concentrations of two metals [zinc (Zn) and vanadium (V)] found commonly in PM and measured changes in spontaneous beat rate. We found statistically significant reductions in spontaneous beat rate after both short-term (4-hr) and long-term (24-hr) exposures, with a more substantial effect seen with Zn. We also measured the expression of genes associated with inflammation and a number of sarcolemmal proteins associated with electrical impulse conduction. Exposure to Zn or V (6.25-50 microM) for 6 hr produced significant increases in IL-6, IL-1 alpha, heat shock protein 70, and connexin 43 (Cx43). After 24 hr exposure, Zn induced significant changes in the gene expression of Kv4.2 and KvLQt (potassium channel proteins), the alpha 1 subunit of the L-type calcium channel, and Cx43, as well as IL-6 and IL-1 alpha. In contrast, V produced a greater effect on Cx43 and affected only one ion channel (KvLQT1). These results show that exposure of rat cardiac myocytes to noncytotoxic concentrations of Zn and V alter spontaneous beat rate as well as the expression of ion channels and sarcolemmal proteins relevant to electrical remodeling and slowing of spontaneous beat rate, with Zn producing a more profound effect. As such, these data suggest that the cardiac effects of PM are largely determined by the relative metal composition of particles.

Animals↗
PubMed1997

Functional analysis of ssaJ and the ssaK/U operon, 13 genes encoding components of the type III secretion apparatus of Salmonella Pathogenicity Island 2.

We have investigated the structure and transcriptional organization of 13 genes of Salmonella Pathogenicity Island 2 (SPI2) that encode components of the second type III secretion apparatus of Salmonella typhimurium. ssaK, L, M, V, N, O, P, Q, R, S, T, U constitute one operon of 10 kb. ssaJ lles upstream of ssaK and is the terminal gene of another operon. The deduced products of ssaJ, ssaK, ssaV, ssaN, ssaO, ssaQ, ssaR, ssaS, ssaT, and ssaU show greatest similarity to the Yersinia spp. genes yscJ, yscL, lcrD, yscN, yscO, yscQ, yscR, yscS, yscT, and yscU, respectively. The products of the ssaL, ssaM and ssaP genes do not have significant similarity to products of other type III secretion systems, and might be important for the specific function of the SPI2 type III secretion system. Bacterial strains carrying different ssa mutations display minor alterations in terms of serum sensitivity when compared with the wild-type strain, but none are defective in replication within macrophage-like RAW 264.7 cells. However, some of the ssa mutant strains invade HEp2 cells less efficiently and are less cytotoxic to RAW 264.7 macrophages than the wild-type strain. We show that the invasion defect is correlated with a lack of SipC in culture supernatants of these mutant strains. SipC is a product of the SPI1 type III secretion system of S. typhimurium, and is important for epithelial cell invasion. Therefore, mutations in SPI2 can affect the SPI1 secretion system, which raises the possibility of an interaction between the two type III secretion systems.

Amino Acid Sequence↗
PubMed2006

Distribution, structure and diversity of "bacterial" genes encoding two-component proteins in the Euryarchaeota.

The publicly available annotated archaeal genome sequences (23 complete and three partial annotations, October 2005) were searched for the presence of potential two-component open reading frames (ORFs) using gene category lists and BLASTP. A total of 489 potential two-component genes were identified from the gene category lists and BLASTP. Two-component genes were found in 14 of the 21 Euryarchaeal sequences (October 2005) and in neither the Crenarchaeota nor the Nanoarchaeota. A total of 20 predicted protein domains were identified in the putative two-component ORFs that, in addition to the histidine kinase and receiver domains, also includes sensor and signalling domains. The detailed structure of these putative proteins is shown, as is the distribution of each class of two-component genes in each species. Potential members of orthologous groups have been identified, as have any potential operons containing two or more two-component genes. The number of two-component genes in those Euryarchaeal species which have them seems to be linked more to lifestyle and habitat than to genome complexity, with most examples being found in Methanospirillum hungatei, Haloarcula marismortui, Methanococcoides burtonii and the mesophilic Methanosarcinales group. The large numbers of two-component genes in these species may reflect a greater requirement for internal regulation. Phylogenetic analysis of orthologous groups of five different protein classes, three probably involved in regulating taxis, suggests that most of these ORFs have been inherited vertically from an ancestral Euryarchaeal species and point to a limited number of key horizontal gene transfer events.

Bacterial Proteins↗
PubMed1998

NADPH oxidase activity and cytochrome b558 content of human Epstein-Barr-virus-transformed B lymphocytes correlate with expression of genes encoding components of the oxidase system.

We investigated the NADPH oxidase activity, cytochrome b558 content, and gene expression of gp91-phox and p47-phox in normal Epstein-Barr-virus (EBV)-transformed B lymphocytes, compared to EBV-transformed B lymphocytes from patients with X-linked chronic granulomatous disease (CGD), normal peripheral blood neutrophils or mononuclear cells, and the A301 or C8166 lymphoblastoid cell lines. CGD phenotypes included both "classic" disease with no detectable gp91-phox protein (termed X91(0)) and "variant" phenotype with reduced but detectable gp91-phox protein (X91(-)). Normal EBV-transformed B lymphocytes show a dose-dependent PMA-induced superoxide release. Culturing these cells with IFN-gamma (100 U/ml) and TNF-alpha (1000 U/ml), alone or in combination for 7 days, caused a modest increase in their NADPH oxidase activity (P > 0.05 in all situations). Normal EBV-transformed B lymphocytes have lower NADPH oxidase activity and cytochrome b558 content than peripheral blood neutrophils or mononuclear cells (P < 0.05 in all situations). In contrast, they have higher NADPH oxidase activity and cytochrome b558 content than X91(-) CGD EBV-transformed B lymphocytes (P < 0.05 in all situations). A301 or C8166 lymphoblastoid cell lines and X91(0) CGD EBV-transformed B lymphocytes have barely detectable NADPH oxidase activity or cytochrome b558 content (P < 0.05 in all situations). Gene expression studies also show a modest increase in expression and transcription rates of gp91-phox and p47-phox genes in normal EBV-transformed B cells cultured with IFN-gamma (100 U/ml) and TNF-alpha (1000 U/ml), alone or in combination for 7 days. We conclude that NADPH oxidase activity and cytochrome b558 content correlate with gp91-phox and p47-phox gene expression in EBV-transformed B lymphocytes.

B-Lymphocytes↗
PubMed2003

The human complement component C1R gene: the exon-intron structure and the molecular basis of allelic diversity.

Human C1r is a component of the complement system, which is a major mediator of innate immunity. In this study we investigated the exon-intron organization of the human C1R gene, which spans 11 kb from the initiation codon to the stop codon, and is very similar in exon-intron structure to the C1S gene. Six common and rare alleles, C1R*1, C1R*2, C1R*5, C1R*8, C1R*9, and C1R*13, were characterized by five mutations at amino acid positions 114, 135, 146, 167 and 244, in exons 4, 5 and 7 where the CUB1, EGF and CUB2 domains are encoded, respectively. A comparison with the cDNA of the mouse C1r gene showed that C1R*2is likely to be an ancestral allele. In addition, nine nucleotide substitutions and one length polymorphism were found in introns 2, 3, 4, 8 and 10.

Amino Acid Sequence↗