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A consensus sequence for long-chain fatty-acid alcohol oxidases from Candida identifies a family of genes involved in lipid omega-oxidation in yeast with homologues in plants and bacteria.

The yeast Candida cloacae is capable of growing on alkanes and fatty acids as sole carbon sources. Transfer of cultures from a glucose medium to one containing oleic acid induced seven proteins of M(r) 102,000, 73,000, 61,000, 54,000, and 46,000 and two in the region of M(r) 45,000 and repressed a protein of M(r) 64,000. The induction of the M(r) 73,000 protein reached a 7-fold maximum 24 h after induction. The protein was confirmed by its enzyme activity to be a long-chain fatty-acid alcohol oxidase (LC-FAO) and purified to homogeneity from microsomes by a rapid procedure involving hydrophobic chromatography. An internal peptide of 30 amino acids was sequenced. A 1100-base pair cDNA fragment containing the LC-FAO peptide coding sequence was used to isolate a single exon genomic clone containing the full-length coding sequence of an LC-FAO (fao1). The fao1 gene product was expressed in Escherichia coli and was translated as a functional long-chain alcohol oxidase, which was present in the membrane fraction. In addition, full-length coding sequences for a Candida tropicalis LC-FAO (faoT) and a second C. cloacae LC-FAO (fao2) were isolated. The DNA sequences obtained had open reading frames of 2094 (fao1), 2091 (fao2), and 2112 (faoT) base pairs. The derived amino acid sequences of fao2 and faoT showed 89.4 and 76.2% similarities to fao1. The fao1 gene is much more highly induced on alkane than is fao2. Although this study describes the first known DNA sequences encoding LC-FAOs from any source, there are unassigned Arabidopsis sequences and an unassigned Mycobacterium sequence in the GenBank(TM) Data Bank that show strong homology to the described LC-FAO sequences. The conservation of sequence between yeast, plants, and bacteria suggests that an as yet undescribed family of long-chain fatty-acid oxidases exists in both eukaryotes and prokaryotes.

Alcohol Oxidoreductases↗

A new marker (NGFB) on pig chromosome 4, isolated by using a consensus sequence conserved among species.

The nerve growth factor beta gene (NGFB) belongs to a conserved syntenic group on human chromosome 1 and mouse Chromosome 3. The objective of this study was the isolation of a part of the porcine NGFB gene and its use as a genetic and physical marker in the pig genome. On the basis of a nucleotide sequence comparison among different species, NGFB-specific primers were chosen to amplify the corresponding porcine sequence by PCR. A pig genomic DNA fragment of 763 bp was isolated, and its DNA sequence, containing the complete coding sequence of mature NGFB, was determined. It was demonstrated that pig NGFB is largely homologous with NGFB of other species (mouse, cattle, chicken) and especially with human NGFB; the isolated clone shows 91% nucleotide and 99% translated amino acid sequence identity to the human NGFB sequence. The porcine DNA clone allowed us to identify an RFLP marker for genetic mapping in pigs and was used to map the NGFB gene to pig chromosome region 4q1.6-->q2.3 by radioactive in situ hybridization. Previously, we had localized to the same chromosome another member of this syntenic group, the gene encoding alpha 1 Na+,K+ ATPase (ATP1A1). These results show that a portion of the homologous region between human chromosome 1 and mouse Chromosome 3 is also conserved on pig chromosome 4.

Amino Acid Sequence↗

Palmitoylation of cysteine 69 from the COOH-terminal of band 3 protein in the human erythrocyte membrane. Acylation occurs in the middle of the consensus sequence of F--I-IICLAVL found in band 3 protein and G2 protein of Rift Valley fever virus.

One of the major physiologic functions of erythrocytes is the mediation of chloride-bicarbonate exchange in the transport of carbon dioxide from the tissues to the lungs. The anion exchange is mediated by a typical polytopic transmembrane protein in the cell membrane, designated Band 3. A carboxyl-terminal peptide of Band 3 was affinity-labeled with pyridoxal phosphate, a substrate for the anion transport system, and then sequenced (Kawano, Y., Okubo, K., Tokunaga, F., Miyata, T., Iwanaga, S., and Hamasaki, N. (1988) J. Biol. Chem. 263, 8232-8238). The 10th amino acid residue of the peptide could not be determined, suggesting post-translational modification of the residue. In the present communication, we have investigated the molecular structure of human Band 3 and the COOH-terminal 8500-dalton peptide using gas-liquid chromatography-mass spectrometry. Band 3 was modified covalently by fatty acids and these acids were released from Band 3 by hydroxylamine treatment at either pH 7 or 11, indicating that the linkage between Band 3 and the fatty acid is a thio ester bond. 1 mol of Band 3 interacted with 1 mol of fatty acid at a cysteine residue located 69 residues from the COOH terminus of Band 3. The fatty acids used in the modification were myristate, palmitate, oleate, and stearate, with palmitate being the major component. The esterified site is close to the site affinity-labeled with pyridoxal phosphate (Kawano, Y., Okubo, K., Tokunaga, F., Miyata, T., Iwanaga, S., and Hamasaki, N. (1988) J. Biol. Chem. 263, 8232-8238). The amino acid sequence including the acylation site was Phe-Thr-Gly-Ile-Gln-Ile-Ile-Cys-Leu-Ala-Val-Leu, which is conserved in the G2 protein of Rift Valley fever virus as Phe-Ser-Ser-Ile-Ala-Ile-Ile-Cys-Leu-Ala-Val-Leu. The G2 protein, like Band 3, is a polytopic transmembrane protein. Although acylation of the cysteine residue of G2 protein has not been examined, the Phe-X-X-Ile-X-Ile-Ile-Cys-Leu-Ala-Val-Leu sequence could be a common motif for fatty acylation of certain membrane proteins.

Acylation↗

Differential requirement of IFN consensus sequence binding protein for the production of IL-12 and induction of Th1-type cells in response to IFN-gamma.

IFN-gamma exerts multiple biological activities in the modulation of immune responses by the induction of transcription factors. One transcriptional factor of the IFN regulatory factor family found to be critical in regulating IL-12-dependent IFN-gamma production in vivo following infectious challenge has been designated IFN consensus sequence-binding protein (ICSBP). In this study, the role of ICSBP in regulating type 1 responses to T cell-specific stimulation in vitro was assessed. Total splenocytes from ICSBP-/- mice stimulated with soluble anti-CD3 were markedly impaired in the production of IFN-gamma compared with similarly stimulated cells from ICSBP+/+ mice. Consistent with the decrease in IFN-gamma production, splenocytes from ICSBP-/- mice stimulated with anti-CD3 in the presence or absence of IFN-gamma or a soluble CD40 ligand agonist failed to produce IL-12 p40 and IL-12 p70 protein; however, the deficient production of IFN-gamma from ICSBP-/- mice could be restored by the addition of anti-CD28 Ab in an IL-12-independent manner. In contrast to the previous data, production of IFN-gamma from naive CD4+/LECAM-1high cells of ICSBP-/- mice that had been primed in vitro with anti-CD3 was similar to or greater than that of ICSBP+/+ controls. In addition, the presence of IFN-gamma in priming cultures enhanced both priming for IFN-gamma and IL-12 responsiveness from ICSBP-/- CD4+ T cells. Overall, these results provide evidence that ICSBP is differentially required for the ability of IFN-gamma to regulate type 1 cytokine responses from APCs and CD4+ T cells.

Adjuvants, Immunologic↗

Splicing signals in Drosophila: intron size, information content, and consensus sequences.

A database of 209 Drosophila introns was extracted from Genbank (release number 64.0) and examined by a number of methods in order to characterize features that might serve as signals for messenger RNA splicing. A tight distribution of sizes was observed: while the smallest introns in the database are 51 nucleotides, more than half are less than 80 nucleotides in length, and most of these have lengths in the range of 59-67 nucleotides. Drosophila splice sites found in large and small introns differ in only minor ways from each other and from those found in vertebrate introns. However, larger introns have greater pyrimidine-richness in the region between 11 and 21 nucleotides upstream of 3' splice sites. The Drosophila branchpoint consensus matrix resembles C T A A T (in which branch formation occurs at the underlined A), and differs from the corresponding mammalian signal in the absence of G at the position immediately preceding the branchpoint. The distribution of occurrences of this sequence suggests a minimum distance between 5' splice sites and branchpoints of about 38 nucleotides, and a minimum distance between 3' splice sites and branchpoints of 15 nucleotides. The methods we have used detect no information in exon sequences other than in the few nucleotides immediately adjacent to the splice sites. However, Drosophila resembles many other species in that there is a discontinuity in A + T content between exons and introns, which are A + T rich.

Animals↗

A putative consensus sequence for the nucleotide-binding site of annexin A6.

Reaction-induced infrared difference spectroscopy (RIDS) has been used to investigate the nature of interactions of human annexin A6 (ANXA6) with nucleotides. RIDS results for ANXA6, obtained after the photorelease of GTP-gamma-S, ATP, or P(i) from the respective caged compounds, were identical, suggesting that the interactions between the nucleotide and ANXA6 were dominated by the phosphate groups. Phosphate-induced structural changes in ANXA6 were small and affected only seven or eight amino acid residues. The GTP fluorescent analogue, 2'(3')-O-(2,4,6-trinitrophenyl)guanosine 5'-triphosphate (TNP-GTP), quenched tryptophan fluorescence of ANXA6 when bound to the protein. A binding stoichiometry of 1 mol of nucleotide/mol ANXA6 was established with a K(D) value of 2.8 microM for TNP-GTP. The bands observed on RIDS of ANXA6 halves (e.g., N-terminal half, ANXA6a, and C-terminal half, ANXA6b) were similar to those of the whole molecule. However, their amplitudes were smaller by a factor of 2 compared to those of whole ANXA6. TNP-GTP bound to both fragments of ANXA6 with a stoichiometry of 0.5 mol/mol. However, the binding affinities of ANXA6a and ANXA6b differed from that of ANXA6. Simulated molecular modeling revealed a nucleotide-binding site which was distributed in two distinct domains. Residues K296, Y297, K598, and K644 of ANXA6 were less than 3 A from the bound phosphate groups of either GTP or ATP. The presence of two identical sequences in ANXA6 with the F-X-X-K-Y-D/E-K-S-L motif, located in the middle of ANXA6, at residues 293-301 (within ANXA6a) and at 641-649 (within ANXA6b), suggested that the F-X-X-K-Y-D/E-K-S-L motif was the putative sequence in ANXA6 for nucleotide binding.

Adenosine Triphosphate↗

A blood group-related polymorphism of CD44 abolishes a hyaluronan-binding consensus sequence without preventing hyaluronan binding.

CD44 is a widely expressed integral membrane protein that acts as a receptor for hyaluronan (HA) and is proposed to be important to cell-extracellular matrix interaction. The Indian (In) blood group antigens reside on CD44, and most individuals express the Inb antigen. Homozygosity for the Ina allele occurs as a rare event and is associated with production of alloantibody to the common Inb antigen after transfusion or pregnancy. The present study demonstrates that a single point mutation (G252 --> C) causes an Arg46 --> Pro substitution, which is responsible for the Inb/Ina polymorphism. Additional mutations were found in In(a+b-) cDNA but were not necessary to the antigenic phenotype as determined in site-directed mutagenesis studies. In studies using CD44 chimeric constructs, Arg46 has previously been shown to be crucial for maintenance of HA-binding ability to a CD44 peptide. However, the present study demonstrates that the Arg46 --> Pro substitution does not reduce HA binding to the intact CD44 protein, which contains two proposed extracellular HA-binding motifs. Down-regulation of HA binding to In(a+b-) CD44 by anti-CD44 monoclonal antibody (mAb) ligands, however, was weakened, although all mAbs tested bound In(a+b-) and In(a-b+) CD44 equally well. Competitive inhibition studies using human anti-Inb also showed that some mAbs that inhibit HA binding to CD44 may do so by interacting with a domain separate from, but affecting the structure of, the Inb epitope.

Amino Acid Sequence↗

Cleavage at the furin consensus sequence RAR/KR(109) and presence of the intervening peptide of the respiratory syncytial virus fusion protein are dispensable for virus replication in cell culture.

Proteolytic processing of the respiratory syncytial virus F (fusion) protein results in the generation of the disulfide-linked subunits F1 and F2 and in the release of pep27, a glycopeptide originally located between the two furin cleavage sites FCS-1 (RKRR(136)) and FCS-2 (RAR/KR(109)). We made use of reverse genetics to study the importance of FCS-2 and of pep27 for BRSV replication in cell culture. Replacement of FCS-2 in the F protein of recombinant viruses by either of the sequences NANR(109), RANN(109) or SANN(109), respectively, abolished proteolytic processing at this position, whereas the cleavage of FCS-1 was not affected. All mutants replicated in calf kidney and Vero cells in the absence of exogenous trypsin, although somewhat higher titers of BRSV containing the NANR(109) or the RANN(109) motif were achieved in the presence of trypsin. The virus mutants showed a reduced cytopathic effect which was lowest in the case of the SANN(109) mutant. These findings demonstrate that cleavage at FCS-2 is dispensable for replication of respiratory syncytial virus in cell culture. A deletion mutant containing FCS-1 but lacking FCS-2 and most of pep27 replicated in cell culture as efficiently as the parental virus, indicating that this domain of the F protein is not essential for virus maturation and infectivity.

Amino Acid Sequence↗

Diversity of antibody binding to V3 peptides representing consensus sequences of HIV type 1 genotypes A to E: an approach for HIV type 1 serological subtyping.

We investigated whether V3-binding assays might be useful to analyze human immunodeficiency virus type 1 (HIV-1) variants in different geographic regions. We showed that strong cross-reactivity between subtype-specific V3 peptides is almost inevitable in standard indirect enzyme-linked immunosorbent assays (EIA), impairing precise serological subtyping. We therefore developed a subtype-specific EIA (HIV-1 SSEIA) that uses the principle of blocking by an excess of peptide in the liquid phase. Using 231 serum samples collected from HIV-1-infected individuals in 10 different geographical areas from 4 continents, we showed that this approach detected the dominant subtype reactivity in more than 97% of the cases. Internal controls (0 and 100% blocking) were used for every sample such that comparative analysis was possible, independent of both the individual humoral response and the time of collection during the course of infection. This was validated by the excellent concordance of the serological profiles of couples and the temporal stability of the serological profile in individuals. The geographical distribution of the various subtypes in the SSEIA was in agreement with the present knowledge of the distribution of the various genotypes. Although the goal of this study was not an extensive seroepidemiological survey, our results showed that the various profiles in most of the regions were relatively homogeneous, but in central Africa there was a large diversity of serological profiles. Cluster analysis identified a limited number of V3 serogroups of serotypes within the HIV-1 group M. Five serogroups, some of them divided into subgroups, were identified and characterized by a mean serological profile. Our data confirmed that subtypes A and C, although being dissimilar genetic subtypes, present conserved antigenic properties in the V3 region, and that the D subtype is probably the most divergent within the group M (B Korber et al., J Virol 1994;68:6730). Cluster analysis showed a clear correlation between position within the dendrogram and geographical origin of the samples. This is further support for the reliability and thereof the usefulness of the SSEIA. This simple methodology may help facilitate the analysis of the distribution of various HIV-1 subtypes circulating in different populations and regions.

Amino Acid Sequence↗

IS231A insertion specificity: consensus sequence and DNA bending at the target site.

In its natural host, Bacillus thuringiensis, the insertion sequence IS231A is preferentially inserted into the terminal inverted repeats of the transposon Tn4430. Using a novel transposition assay, we demonstrate that the Tn4430 ends behave as insertion hot spots for IS231A in Escherichia coli. Sequence analysis reveals that IS231A insertion sites match the 5'-GGG(N)5CCC-3' consensus. However, this consensus is not the only determinant of IS231A insertion specificity. Although both Tn4430 ends have identical sequences, one is strongly preferred to the other and the orientation of insertion into this end is not random. We demonstrate that this preference is determined by the flanking regions of the site. These regions display a conserved periodic organization of their sequence which, by conferring anisotropic flexibility, would induce the DNA to bend in a roughly 'S'-shaped structure centered on the target consensus. DNA conformation analysis by polyacrylamide gel electrophoresis indeed shows that the preferred target site of IS231A is flanked by DNA segments curved in opposite directions. We present a model in which DNA bendability and curvature would contribute to the positioning of IS231A transposase on the target DNA.

Bacillus thuringiensis↗

TA-repeat microsatellites are closely associated with ARS consensus sequences in yeast chromosome III.

Microsatellites are repeats of very short sequences of DNA, interspersed in the genome. In this paper, the occurrence of the two-base repeat microsatellites has been investigated in the DNA sequence of yeast chromosome III. Only AT-repeats were found at a significantly high frequency. Some of the regions with the highest concentration of AT-repeats were located and further analysed, showing a close association with the core consensus of autonomously replicating sequences.

Base Sequence↗

Orangutan alpha-satellite monomers are closely related to the human consensus sequence.

Alpha-satellite is a family of tandemly repeated DNA found at the centromeric regions of all human and primate chromosomes. Human alpha-satellite subsets are largely chromosome-specific and have been further grouped into four suprachromosomal families (SFs), each characterized by a unique set of monomeric types. Although chimpanzee and gorilla alpha-satellites share sufficient sequence similarity to fit the established SFs, the assumption that the derived human alpha-satellite consensus and monomeric types represent the sequence of ancestral repeats remains unestablished. By using oligonucleotide primers specific for a conserved region of human alpha-satellite DNA, we have PCR amplified, cloned, and characterized alpha-satellite sequences from the orangutan genome. Nucleotide sequence analysis demonstrated that orangutan alpha-satellite is formed by a single monomeric type that is significantly closer in percentage of sequence identity (mean = 92%, range = 89-96%) to the overall consensus of human alpha-satellite than to the monomeric types corresponding to the four SFs. Use of cloned sequences as hybridization probes to orangutan genomic DNA digested with a panel of restriction enzymes showed that most orangutan alpha-satellite subsets are characterized by a monomeric construction. The subset homologous to clone PPY2-5 is organized in distinct higher-order repeat structures consisting of 18 adjacent monomers. By FISH two clones, PPY3-4 and PPY3-5, proved to be specific for the alpha-satellite on the orangutan homologs of human Chromosomes (Chrs) 10 and 8, respectively. Our data indicate that there was an ancestral monomeric type displaying high sequence similarity to the overall human consensus from which the different great ape and human subsets and SFs may have originated.

Animals↗

Binding of the Wilms' tumor locus zinc finger protein to the EGR-1 consensus sequence.

The Wilms' tumor locus (WTL) at 11p13 contains a gene that encodes a zinc finger-containing protein that has characteristics of a DNA-binding protein. However, binding of this protein to DNA in a sequence-specific manner has not been demonstrated. A synthetic gene was constructed that contained the zinc finger region, and the protein was expressed in Escherichia coli. The recombinant protein was used to identify a specific DNA binding site from a pool of degenerate oligonucleotides. The binding sites obtained were similar to the sequence recognized by the early growth response-1 (EGR-1) gene product, a zinc finger-containing protein that is induced by mitogenic stimuli. A mutation in the zinc finger region of the protein originally identified in a Wilms' tumor patient abolished its DNA-binding activity. These results suggest that the WTL protein may act at the DNA binding site of a growth factor-inducible gene and that loss of DNA-binding activity contributes to the tumorigenic process.

Amino Acid Sequence↗

The antioxidant responsive element. Activation by oxidative stress and identification of the DNA consensus sequence required for functional activity.

We have characterized further the antioxidant responsive element (ARE) identified in the 5'-flanking region of the rat glutathione S-transferase Ya subunit gene and the NAD(P)H:quinone reductase gene by mutational and deletion analyses. Our data suggest that the sequence, 5'-puGTGACNNNGC-3' 3'-pyCACTGNNNCG-5' where N is any nucleotide, represents the core sequence of the ARE required for transcriptional activation by phenolic antioxidants and metabolizable planar aromatic compounds (e.g. beta-naphthoflavone and 3-methylcholanthrene). We also have found that the ARE is responsive to hydrogen peroxide and phenolic antioxidants that undergo redox cycling. These latter data suggest that the ARE is responsive to reactive oxygen species and thus may represent part of a signal transduction pathway that allow eukaryotic cells to sense and respond to oxidative stress.

Animals↗

Transmembrane domain prediction and consensus sequence identification of the oligopeptide transport family.

Few polytopic membrane proteins have had their topology determined experimentally. Often, researchers turn to an algorithm to predict where the transmembrane domains might lie. Here we use a consensus method, using six different transmembrane domain prediction algorithms on six members of the oligopeptide transport family, all of which have been experimentally characterized. PSI-BLAST results indicate that the six chosen oligopeptide transport family members are distributed throughout most branches of the phylogram, suggesting that these members represent a broad view of the oligopeptide transport family. We combined the prediction algorithms with a multiple sequence alignment, and consensus transmembrane domains were assigned not only based on algorithmic output, but also based on conserved familial motifs found by analysis of the PSI-BLAST results. The consensus method combined with the "charge-difference rule" yields a model topology for the family containing 12 transmembrane domains with the N- and C-termini facing extracellular.

Algorithms↗

Interpreting consensus sequences based on plurality rule.

Our goal is to help researchers interpret the results of a function, based on the concept of plurality rule, that calculates a consensus of a profile of molecular bases. By expressing the plurality rule function as a composition of simpler functions, we obtain both an algorithm to calculate the consensus result and an upper bound on the number of nonequivalent results. Consequently, when used to analyze molecular sequences such as DNA or RNA, the plurality rule function yields at most 48 nonequivalent consensus results. For problems of reasonable size, we describe an algorithm to calculate the probability that each consensus result would occur if the bases were equally likely to appear at every position of the plurality rule function's input profile.

Algorithms↗