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At least 55 records · Page 3Linked to original sources
PubMed1994

Pseudomonas aeruginosa possesses homologues of mammalian phenylalanine hydroxylase and 4 alpha-carbinolamine dehydratase/DCoH as part of a three-component gene cluster.

Pseudomonas aeruginosa possesses a multigene operon that includes phenylalanine hydroxylase (PhhA; phenylalanine 4-monooxygenase, EC 1.14.16.1). phhA encodes PhhA (M(r) = 30,288), phhB (M(r) = 13,333) encodes a homologue of mammalian 4 alpha-carbinolamine dehydratase/homeodomain protein transregulator, and phhC encodes an aromatic aminotransferase (M(r) = 43,237). The reading frames specifying phhB and phhC overlap by 2 bases. The P. aeruginosa PhhA appears to contain iron and is pterin dependent. Unlike the multimeric mammalian hydroxylase, the native P. aeruginosa enzyme is a monomer. The P. aeruginosa PhhA is homologous with mammalian PhhA, tryptophan hydroxylase, and tyrosine hydroxylase. Expression of PhhA from its native promoter required phhB. This may suggest a positive regulatory role for phhB, consistent with the dual catalytic and regulatory roles of the corresponding mammalian homologue.

Amino Acid Sequence↗
PubMed1995

Molecular analysis of the two-component genes, ompR and envZ, in the symbiotic bacterium Xenorhabdus nematophilus.

In Escherichia coli the histidine kinase sensor protein, EnvZ, undergoes autophosphorylation and subsequently phosphorylates the regulatory protein, OmpR. Modulation of the levels of OmpR-phosphate controls the differential expression of ompF and ompC. While the phosphotransfer reaction between EnvZ and OmpR has been extensively studied, the domains involved in the sensing function of EnvZ are not well understood. We have used a comparative approach to study the sensing function of EnvZ. During our search of numerous bacteria we found that the symbiotic/pathogenic bacterium Xenorhabdus nematophilus contained the operon encoding both ompR and envZ. Nucleotide sequence analysis revealed that EnvZ of X. nematophilus (EnvZX.n.) is composed of 342 amino acid residues, which is 108 residues shorter than EnvZ of E. coli (EnvZE.c.). Amino acid sequence comparison showed that the cytoplasmic domains of the EnvZ molecules shared 57% sequence identity. In contrast, the large hydrophilic periplasmic domain of EnvZE.c. was absent in EnvZX.n., and was replaced by a shorter hydrophobic region. Although the periplasmic domains had diverged extensively, envZX.n. was able to complement a delta envZ strain of E. coli. OmpF and OmpC were differentially produced in response to changes in medium osmolarity in this strain. Further genetic analysis established that heterologous phosphorylation between EnvZX.n. and OmpR of E. coli (OmpRE.c.) accounted for the complementation of the delta envZ strain. In addition we show that the OmpR molecules of X. nematophilus and E. coli share 78% amino acid sequence identity. These results indicate that the EnvZ protein of X. nematophilus was able to sense these changes in the osmolarity of the growth environment and properly regulate the levels of OmpR-phosphate in E. coli.

Amino Acid Sequence↗
PubMed1994

Insulin and insulin-like growth factor system components gene expression in the chicken retina from early neurogenesis until late development and their effect on neuroepithelial cells.

To better understand the role of insulin-related growth factors in neural development, we have characterized by in situ hybridization in chicken embryonic retina the patterns of gene expression for insulin, insulin-like growth factor I (IGF-I), their respective receptors and the IGF binding protein 5 (IGFBP5) from early stages (E6) until late stages (E18)--an analysis not performed yet in any species. In addition, we studied the effect of insulin and IGF-I on cultured neuroepithelial cells. Insulin receptor mRNA and IGF-I receptor mRNA were both present and showed a similar, widespread pattern throughout retina development. Insulin mRNA could be detected only by reverse transcription coupled to polymerase chain reaction. IGF-I mRNA was concentrated in the ciliary processes and extraocular muscles early in development (embryonic day 6; E6) and in maturing retinal ganglion cells subsequently (E9-15). IGFBP5 mRNA was preferentially localized in the more differentiated central retinal zone and was maximally concentrated in the inner nuclear and ganglion cell layers at E9. These findings suggest a near constitutive expression of insulin receptor and IGF-I receptor genes, while IGF-I and IGFBP5 showed a highly focal spatiotemporal regulation of gene expression. Insulin and IGF-I, already at 10(-8) M, increased the proportion of PM1-positive neuroepithelial cells found in E5 retinal cultures without affecting significantly the total number of proliferating cells. Together, these data support the finding that, during early neurogenesis in chicken retina, insulin and IGF-I have a specific paracrine/autocrine action. This action, as well as possible effects elicited subsequently, may be dictated by restricted-local synthesis of the ligands and limited access to the factors contained in the vitreous humour. In the case of IGF's role, local IGFBPs expression can contribute to the fine modulation.

Animals↗
PubMed2004

Evaluation of tissue specificity and expression strength of rice seed component gene promoters in transgenic rice.

Using stable transgenic rice plants, the promoters of 15 genes expressed in rice seed were analysed for their spatial and temporal expression pattern and their potential to promote the expression of recombinant proteins in seeds. The 15 genes included 10 seed storage protein genes and five genes for enzymes involved in carbohydrate and nitrogen metabolism. The promoters for the glutelins and the 13 kDa and 16 kDa prolamins directed endosperm-specific expression, especially in the outer portion (peripheral region) of the endosperm, whilst the embryo globulin and 18 kDa oleosin promoters directed expression in the embryo and aleurone layer. Fusion of the GUS gene to the 26 kDa globulin promoter resulted in expression in the inner starchy endosperm tissue. It should be noted that the 10 kDa prolamin gene was the only one tested that required both the 5' and 3' flanking regions for intrinsic endosperm-specific expression. The promoters from the pyruvate orthophosphate dikinase (PPDK) and ADP-glucose pyrophosphorylase (AGPase) small subunit genes were active not only in the seed, but also in the phloem of vegetative tissues. Within the seed, the expression from these two promoters differed in that the PPDK gene was only expressed in the endosperm, whereas the AGPase small subunit gene was expressed throughout the seed. The GUS reporter gene fused to the alanine aminotransferase (AlaAT) promoter was expressed in the inner portion of the starchy endosperm, whilst the starch branching enzyme (SBE1) and the glutamate synthase (GOGAT) genes were mainly expressed in the scutellum (between the endosperm and embryo). When promoter activities were examined during seed maturation, the glutelin GluB-4, 26 kDa globulin and 10 kDa and 16 kDa prolamin promoters exhibited much higher activities than the others. The seed promoters analysed here exhibited a wide variety of activities and expression patterns, thus providing many choices suitable for various applications in plant biotechnology.

Journal Article↗
PubMed1984

Transcription of ribosomal component genes and lac in a relA+/relA pair of Escherichia coli strains.

To determine the stringent response, a repression of gene activity during amino acid starvation assumed to be mediated by the effector necleotide guanosine tetraphosphate (ppGpp), of metabolically regulated constitutive genes, we measured the transcription of ribosomal protein genes, the constitutive lac operon, and stable RNA genes in a variety of growth media and after amino acid starvation in a relA+/relA pair of Escherichia coli B/r strains. For rRNA and tRNA (stable RNA) it has previously been shown that the distinction between stringent control and growth rate control is unfounded, as the function describing the stable RNA gene activities at different concentrations of guanosine tetraphosphate is independent of growth conditions (exponential growth or amino acid starvation) and of the relA allele present. Here, the results indicated that the stringent responses of ribosomal protein genes and lac differ from their metabolic control during exponential growth in different media. This can be explained by polarity and RNA polymerase sink effects during amino acid starvation which are irrelevant for stable RNA genes but which are superimposed on mRNA gene activities.

Amino Acids↗
PubMed1992

The organization and expression of essential transcription translation component genes in the extremely thermophilic eubacterium Thermotoga maritima.

A 5789-nucleotide-long EcoRI fragment from the genome of Thermotoga maritima, identified by cross-hybridization to L11, L1, L10, and L12 ribosomal protein gene sequences from Escherichia coli, was cloned and sequenced. The fragment encodes five tRNAs (tRNA(met1), anticodon complementary to AUG; tRNA(met2), AUG; tRNA(thr), ACA; tRNA(tyr), UAC; tRNA(trp), UGG), the transcription termination-antitermination factor nusG, the four 50 S subunit ribosomal proteins L11, L1, L10, and L12, and the amino-terminal portion of the RNA polymerase beta subunit protein. The five tRNA genes, the nusG gene, and the L11, L1, L10, and L12 ribosomal protein genes form a complex transcription unit. Transcripts appear to be initiated from an upstream promoter, P1, located in front of the tRNA(met1) gene and from three internal promoters: P2 is located immediately in front of the tRNA(met2) gene; PL10 is near the beginning of the L1-L10 intergenic space, and PL12 is at the end of the L10 gene sequence. The tRNA sequences are excised from the leader regions of the P1- and P2-initiated transcripts. Three putative but potentially important regulatory sequences were identified within this operon: an L1 translational control site, a transcription attenuator, and a strong rho-independent terminator. The strong terminator located distal to the L12 gene overlaps a fifth promoter, P beta, which is used to initiate transcripts of the downstream RNA polymerase beta subunit gene. The T. maritima NusG protein exhibits 43% amino acid sequence identity when aligned to the E. coli protein; the alignment is interrupted by a large 171-amino acid-long insertion into the T. maritima protein after codon 45.

Amino Acid Sequence↗
PubMed1991

Structure of the murine fifth complement component (C5) gene. A large, highly interrupted gene with a variant donor splice site and organizational homology with the third and fourth complement component genes.

To understand fifth complement component (C5) gene regulation, splicing, and C5 protein deficiency at the molecular level, the organization of the murine C5 gene was determined. The C5 structural gene is present as a single copy in the mouse genome as demonstrated by Southern blot analysis. Accordingly, three cosmid clones were isolated from a genomic library that was prepared from mouse strain B10.D2/nSnJ. These clones overlapped and contained the structural gene encoding the complete C5 alpha-chain and 90% of the beta-chain. The 5'-flanking region of the C5 gene was obtained from a clone isolated from a genomic lambda-MOPC-41 library. Unique restriction fragments were prepared from the genomic clones and subcloned, and the exons were sequenced. All introns were sized by sequencing or Southern analysis. The C5 structural gene was found to be a highly interrupted gene of approximately 78 kilobases containing 42 exons and 41 introns. The exons ranged in length from 58 to 247 base pairs, with an average length of 131 base pairs. The introns ranged in size from 100 base pairs to 4 kilobases with an average length of 1.5 kilobases. The C5 alpha-chain was encoded by 49 kilobases containing 26 exons; the beta-chain was encoded by 29 kilobases containing 16 exons. The C5a coding sequence was split between two exons. All intron/exon junctions followed the normal consensus rule except at intron 35 in which the 5'-donor GT was substituted by GC. The 2-base-pair gene deletion and HindIII and PvuII restriction fragment length polymorphisms associated with murine C5 deficiency were localized to exon 7, exon 16, and intron 20, respectively. Comparison of the intron-exon junctions of the murine C5, human C3, and mouse C4 genes indicated that these genes are nearly identical in structural organization. However, the rat alpha 2-macroglobulin gene showed only moderate genomic organizational similarity to the murine C5 gene. A major and a minor transcriptional initiation site in the C5 gene were identified by primer extensions and confirmed by RNase protection assays. Sequence analysis of the 5'-flanking region (760 base pairs) revealed a TATA-like and CAAT box upstream of the major transcriptional initiation site at positions -274 and -303, respectively, suggesting an atypical promoter. The 5'-flanking region also contained sequences identical with several cis-acting motifs known to bind the liver-specific nuclear protein LF-A1 and the nuclear protein NF-kappa B.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Similarity in nucleotide sequence of the gene encoding nontoxic component of botulinum toxin produced by toxigenic Clostridium butyricum strain BL6340 and Clostridium botulinum type E strain Mashike.

The complete nucleotide and deduced amino acid sequence of the nontoxic component of botulinum type E progenitor toxin is determined in recombinant plasmid pU9BUH containing about 6.0 kb HindIII fragment obtained from chromosomal DNA of Clostridium butyricum strain BL6340. The open reading frame (ORF) of this nontoxic component gene is composed of 3,486 nucleotide bases (1,162 amino acid residues). The molecular weight calculated from deduced amino acid residues is estimated 13,6810.1. The present study revealed that 33 nucleotide bases of 3,486 are different in the nontoxic component gene between C. butyricum strain BL6340 and C. botulinum type E strain Mashike. This corresponds to the difference of 17 amino acid residues in these nontoxic component.

Amino Acid Sequence↗
PubMed1985

Mapping of steroid 21-hydroxylase genes adjacent to complement component C4 genes in HLA, the major histocompatibility complex in man.

The genes for four components (C) of complement in the human major histocompatibility complex (HLA) have been aligned previously in a series of overlapping cosmid cloned inserts. Those inserts, which contained the two C4 genes C4A and C4B, hybridized with human adrenal mRNA, indicating that they contain a gene expressed in the adrenal. The mRNA fraction of 2.4 kilobases (kb) hybridizes with genomic DNA of 4.5 kb, which is duplicated and lies about 1.5 kb 3' of both the C4A and the C4B complement genes. Sequencing of a 430-base section and comparison with the published cDNA sequence of bovine cytochrome P-450 21-hydroxylase, peptide sequences of porcine 21-hydroxylase, and a cDNA sequence of a rat liver cytochrome P-450 identified the gene as coding for human steroid 21-hydroxylase [steroid,hydrogen-donor:oxygen oxidoreductase (21-hydroxylating), EC 1.14.99.10]. Mapping of the gene was helped by use of a synthetic oligonucleotide based on the bovine cDNA sequence.

Adrenal Glands↗
PubMed2003

The expression of genes encoding visual components is regulated by a circadian clock, light environment and age in the honeybee (Apis mellifera).

The honeybee, Apis mellifera, has been used as a model to study the development of the visual system and adult bee behaviour. However, the regulation of the levels of visual component genes has never been addressed in this organism. We isolated honeybee cDNAs encoding green-sensitive opsin and visual arrestin and then measured their mRNA levels in honeybee workers. Both mRNAs fluctuate on a daily cycle that depends on a pacemaker that functions separately from the pacemaker which controls rhythmic locomotor activity. The cycling-patterns of opsin and arrestin mRNAs are different from each other and are modified by light. Furthermore, light exposure can increase the absolute levels of both mRNAs and the arrestin mRNA level is also dependent on age. Consistent with these results, both mRNA levels are higher in foragers than in in-hive bees under natural conditions. This study thus shows that the expression of genes encoding visual components is regulated by multiple factors and is adjusted to the honeybees' need for vision during the day, and throughout their lives. Comparison of data obtained with honeybees and other organisms indicates that there is a link between the regulation of phototransduction components and vision-related animal behaviour.

Aging↗
PubMed1996

Carbon source regulation of PIS1 gene expression in Saccharomyces cerevisiae involves the MCM1 gene and the two-component regulatory gene, SLN1.

The Saccharomyces cerevisiae PIS1 gene encodes phosphatidylinositol synthase. The amount of phosphatidylinositol synthase is not affected by the presence of inositol and choline in the growth medium. This is unusual because the amounts and/or activities of other phospholipid biosynthetic enzymes are affected by these precursors, and the promoter of the PIS1 gene contains a sequence resembling the regulatory element that coordinates the inositol-mediated regulation (UASINO). We found that transcription of the PIS1 gene was insensitive to inositol and choline and did not require the putative UASINO regulatory sequence or the cognate regulatory genes (INO2 and OPI1). The PIS1 promoter includes sequences (MCEs) that bind the Mcm1 protein. Because the Mcm1 protein interacts with both the Sln1 and the Gal11 regulatory proteins, we examined the effect of mutant alleles of the MCM1 and SLN1 genes and carbon source on expression of the PIS1 gene. We found that expression of the PIS1 gene was reduced when cells were grown in a medium containing glycerol and increased when grown in a medium containing galactose relative to cells grown in a glucose medium. The glycerol-mediated repression of PIS1 gene expression required both the MCM1 gene and the MCEs, whereas the SLN1 gene was required for full galactose-mediated induction of a PIS1-lacZ reporter gene. Thus, PIS1 gene expression is unique among the phospholipid biosynthetic structural genes because it is uncoupled from the inositol response and regulated in response to the carbon source. This is the first example in yeast of a complete circuit linking a stimulus (carbon source) to gene regulation (PIS1) using a two-component regulator (SLN1).

Base Sequence↗
PubMed2004

A pair of two-component regulatory genes ecrA1/A2 in S. coelicolor.

Two-component genes are kinds of genetic elements involved in regulation of antibiotic production in Streptomyces coelicolor. DNA microarray analysis revealed that ecrA1/A2, which mapped at distant sites from red locus and encode respectively the kinase and regulator, expressed coordinately with genes of Red specific biosynthetic pathway. ecrA1 and ecrA2 gene-disruptive mutants were constructed using homogenotisation by reciprocal double crossover. Fermentation data showed that the undecylprodigiosin (Red) level of production was lower than that of wild-type strain. However, the change of the actinorhodin (Act) production level was not significant compared with wild type. Thus, these experiment results confirmed that the two-component system ecrA1/A2 was positive regulatory element for red gene cluster.

Anthraquinones↗
PubMed2003

Characterisation of a gene cluster in Fugu rubripes containing the complement component C4 gene.

In this study, we describe the characterisation of the complement component C4 gene in Fugu rubripes. The Fugu C4 gene, orthologous to the tetrapod C4 gene, encompasses a genomic span of 9702 base pairs and contains 41 exons, encoding the typical C4 three-chain polypeptide. The gene encodes a protein containing 1703 amino acids. The Fugu C4 protein demonstrates the presence of 25 conserved cysteine residues, as well as conservation of the functionally important thioester site. Complete sequencing of one cosmid and sequence scans from a cluster of 18 overlapping BAC clones, centering around the C4 gene, have identified the short-range linkage with five orthologous human genes mapping to the Major Histocompatibility Complex (MHC) including: tenascin X (TNX); cytochrome P450, subfamily XXIA, polypeptide 2 (CYP21A2); allograft inflammatory factor 1 (AIF1) and casein kinase 2, beta polypeptide (CSNK2B), all found in the MHC class III region; and retinoid X receptor, beta (RXRB),which resides in the MHC extended class II region. To date, this syntenic association of the Fugu C4 and other MHC class III region genes has not been observed in other teleost fish. Data from the recent whole-genome shotgun assemblies reveal the Fugu MHC-related cluster of genes to be flanked predominantly by genes mapping to human chromosomes 7 and 19. All of the six identified Fugu MHC-related genes have been characterised at the genomic level.

Amino Acid Sequence↗