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Herpes simplex virus 1 protein kinase is encoded by open reading frame US3 which is not essential for virus growth in cell culture.

Earlier reports have described a novel protein kinase in cells infected with herpes simplex or pseudorabies viruses. These novel enzymes were characterized by their acceptance of protamine as a substrate and by their differential chromatographic behavior in anion-exchange chromatography. We report that this activity was not present in extracts of uninfected cells or of cells infected with a mutant constructed so as to contain a deletion in the US3 open reading frame mapping in the small component of herpes simplex virus 1 DNA. The activity was present in extracts of cells infected with wild-type virus and with a recombinant in which the US3 open reading frame had been rescued. Our results are consistent with the observation reported earlier that the coding sequences predict an amino acid motif common to protein kinases and lead to the conclusion that the US3 open reading frame encodes a virus-specific protein kinase that is not required for virus growth in cells in culture.

Amino Acid Sequence↗

Identification of Epstein-Barr virus terminal protein 1 (TP1) in extracts of four lymphoid cell lines, expression in insect cells, and detection of antibodies in human sera.

The terminal proteins TP1 and TP2 are putative products of Epstein-Barr virus (EBV) genes expressed during the latent cycle of the virus. They are predicted to code for 53- and 40-kilodalton integral membrane proteins. We used the baculovirus Autographa californica nuclear polyhedrosis virus as an expression vector to produce TP1 in large amounts in insect cells. The DNA sequences used to express TP1 originated from a TP1 cDNA derived from an M-ABA/CBL1 cDNA library. Rabbit antisera raised against procaryotic TP1 fusion proteins recognized a monomer and a dimer of the recombinant TP1 protein in the infected insect cells. Immunofluorescence studies of living insect cells showed that the recombinant protein is located in the plasma membrane. The insect cells infected with the recombinant baculovirus producing TP1 provided a test system to screen human antisera for TP1 antibodies. A total of 168 human EBV-positive and EBV-negative antisera were studied. TP1 antibodies were detected only in sera from nasopharyngeal carcinoma patients (16 out of 42). Rabbit antiserum raised against the recombinant TP1 protein expressed in the baculovirus system specifically recognized a protein of about 54 kilodaltons in the lymphoblastoid cell lines M-ABA and M-ABA/CBL1 and in the Burkitt's lymphoma cell lines BL18 and BL72. This protein could be located in the total membrane fraction of M-ABA cells and is upregulated by treating the cells with 12-O-tetradecanoylphorbol-13-acetate.

Animals↗

Effect of a modulator deletion on transcription of the human cytomegalovirus major immediate-early genes in infected undifferentiated and differentiated cells.

Differentiation-dependent expression of the human cytomegalovirus (HCMV) major immediate-early (MIE) genes, encoding IE1 and IE2, may partly govern virus replication in monocytic THP-1 and embryonal carcinoma (Tera-2) cells. The modulator of the MIE promoter was shown previously in transient transfection assays to repress transcription from promoter segments in undifferentiated THP-1 and Tera-2 cells but not in differentiated cells. To determine the biological importance of these findings, we constructed a recombinant HCMV (r delta MSVgpt) without a modulator. In comparison to wild-type (WT) virus, r delta MSVgpt exhibits a slight delay in growth in human fibroblasts, but there is no appreciable change in IE1 and IE2 transcription. Moreover, there is no appreciable change in the early/late kinetics of transcription of RNAs colinear with the predicted UL128 coding region, which is adjacent to the modulator, although the size distribution and abundance of these RNAs are altered. In infected undifferentiated THP-1 and Tera-2 cells, WT and r alpha MSVgpt viruses produce minimal but comparable amounts of IE1 RNAs. The genomes of both viruses are detectable in similar amounts within these undifferentiated cells. Induction of cellular differentiation before infection overcomes the block in MIE gene transcription. WT and r alpha MSVgpt infections of differentiated THP-1 cells produce similar levels of IE1 and IE2 RNAs. Thus, differentiation-dependent control of MIE gene transcription involves regulatory mechanisms other than the modulator. Possible alternative functions of the modulator are discussed.

Cell Differentiation↗

RPC53 encodes a subunit of Saccharomyces cerevisiae RNA polymerase C (III) whose inactivation leads to a predominantly G1 arrest.

RPC53 is shown to be an essential gene encoding the C53 subunit specifically associated with yeast RNA polymerase C (III). Temperature-sensitive rpc53 mutants were generated and showed a rapid inhibition of tRNA synthesis after transfer to the restrictive temperature. Unexpectedly, the rpc53 mutants preferentially arrested their cell division in the G1 phase as large, round, unbudded cells. The RPC53 DNA sequence is predicted to code for a hydrophilic M(r)-46,916 protein enriched in charged amino acid residues. The carboxy-terminal 136 amino acids of C53 are significantly similar (25% identical amino acid residues) to the same region of the human BN51 protein. The BN51 cDNA was originally isolated by its ability to complement a temperature-sensitive hamster cell mutant that undergoes a G1 cell division arrest, as is true for the rpc53 mutants.

Amino Acid Sequence↗

Identification of I-plastin, a human fimbrin isoform expressed in intestine and kidney.

The complete cDNA sequence of human intestine-specific plastin (I-plastin) was determined from a clone derived by PCR. It consists of a 97-bp 5' untranslated region, a 1,887-bp coding region, and a 1,655-bp 3' untranslated region. The coding region predicts a 629-residue polypeptide whose sequence displays 86, 75, and 73% identities with chicken intestine fimbrin, human T-plastin, and human L-plastin, respectively. Recombinant I-plastin cross-linked actin filaments into bundles in the absence but not in the presence of calcium. The I-plastin gene was mapped by PCR to human chromosome 3; the L- and T-plastin genes were previously mapped to chromosomes 13 and X, respectively. I-plastin mRNA was detected in the small intestine, colon, and kidneys; relatively lower levels of expression were detected in the lungs and stomach. In contrast, L-plastin expression was restricted to the spleen and other lymph node-containing organs, while T-plastin was expressed in a variety of organs, including muscle, brain, uterus, and esophagus. In contrast to the situation for the intestine, high levels of L- and T-plastin mRNAs were detected in Caco-2, a human colon-derived cell line. Immunofluorescence microscopy detected I-plastin in the brush border of the small intestine and colon. These results identify I-plastin as the human homolog of chicken intestine fimbrin and as a third plastin isoform in humans.

Amino Acid Sequence↗

The two alpha-tubulin genes of Chlamydomonas reinhardi code for slightly different proteins.

Full-length cDNA clones corresponding to the transcripts of the two alpha-tubulin genes in Chlamydomonas reinhardi were isolated. DNA sequence analysis of the cDNA clones and cloned gene fragments showed that each gene contains 1,356 base pairs of coding sequence, predicting alpha-tubulin products of 451 amino acids. Of the 27 nucleotide differences between the two genes, only two result in predicted amino acid differences between the two gene products. In the more divergent alpha 2 gene, a leucine replaces an arginine at amino acid 308, and a valine replaces a glycine at amino acid 366. The results predicted that two alpha-tubulin proteins with different net charges are produced as primary gene products. The predicted amino acid sequences are 86 and 70% homologous with alpha-tubulins from rat brain and Schizosaccharomyces pombe, respectively. Each gene had two intervening sequences, located at identical positions. Portions of an intervening sequence highly conserved between the two beta-tubulin genes are also found in the second intervening sequence of each of the alpha genes. These results, together with our earlier report of the beta-tubulin sequences in C. reinhardi, present a picture of the total complement of genetic information for tubulin in this organism.

Amino Acid Sequence↗

Pruning of a large network by optimal brain damage and surgeon: an example from biological sequence analysis.

Optimal Brain Damage (OBD) and Optimal Brain Surgeon (OBS) represent two popular pruning procedures; however, pruning large networks trained on voluminous data sets using these methods easily becomes intractable. We present a number of approximations and discuss practical issues in real-world pruning, and use as an example a network trained to predict protein coding regions in DNA sequences. The efficiency of OBS on large networks is compared to OBD, and it turns out that OBD is preferable to OBS, since more weights can be removed using less computational effort.

Base Sequence↗

Primary structure and functional properties of an epithelial K channel.

Expression cloning in Xenopus oocytes was used to identify a clone for a renal K channel. The clone, named ROMK2, was obtained from a cDNA library constructed in the plasmid vector pSPORT using size-selected poly(A)+ RNA from whole rat kidney. ROMK2 consists of 1,837 nucleotides, with an open reading frame of 1,116 bases predicted to code for a 372-amino acid peptide. The clone appears to be a splice variant of a recently reported K channel (ROMK1) from rat renal outer medulla (Ho, K.H., C.G. Nichols, W.J. Lederer, J. Lytton, P.M. Vassilev, M.V. Kanazirska, and S.C. Hebert. Nature Lond. 362: 31-37, 1993). Northern blot analysis indicates that ROMK2 is expressed in renal cortex, medulla, and papilla. Expression in other tissues appears to be much lower. The functional properties of the channel as measured in Xenopus oocytes indicate its close relationship to ROMK1 and more distant relationship to the inward rectifier K channel (IRK1) (Kubo, Y, T.J. Baldwin, Y. N. Jan, and L. Y. Jan. Nature Lond. 362: 127-133, 1993). The inward conductance of the channel is a saturable function of external K, with a half-maximal conductance at <5 mM. The selectivity sequence for ion permeability based on reversal potential measurements was K > Rb > NH4 > Na, Li. The conductance to Rb was only one-half that to K. Extracellular Ba2+ and Cs+ blocked the channel in a voltage-dependent manner. The high sensitivity of Cs+ block to voltage is consistent with the channel's operating as a multi-ion pore. The channel was blocked by high concentrations (100 microM) of glibenclamide. It did not appear to be blocked by extracellular Na+ or tetraethyl-ammonium ion. Patch-clamp measurements indicated a single-channel conductance of 30 pS in the presence of 110 mM K and high open probability that was weakly dependent on voltage. This channel may be involved in maintaining the membrane potential of renal cells and/or mediating renal K secretion.

Amino Acid Sequence↗

Learned dynamics of reaching movements generalize from dominant to nondominant arm.

Accurate performance of reaching movements depends on adaptable neural circuitry that learns to predict forces and compensate for limb dynamics. In earlier experiments, we quantified generalization from training at one arm position to another position. The generalization patterns suggested that neural elements learning to predict forces coded a limb's state in an intrinsic, muscle-like coordinate system. Here, we test the sensitivity of these elements to the other arm by quantifying inter-arm generalization. We considered two possible coordinate systems: an intrinsic (joint) representation should generalize with mirror symmetry reflecting the joint's symmetry and an extrinsic representation should preserve the task's structure in extrinsic coordinates. Both coordinate systems of generalization were compared with a naïve control group. We tested transfer in right-handed subjects both from dominant to nondominant arm (D-->ND) and vice versa (ND-->D). This led to a 2 x 3 experimental design matrix: transfer direction (D-->ND/ND-->D) by coordinate system (extrinsic, intrinsic, control). Generalization occurred only from dominant to nondominant arm and only in extrinsic coordinates. To assess the dependence of generalization on callosal inter-hemispheric communication, we tested commissurotomy patient JW. JW showed generalization from dominant to nondominant arm in extrinsic coordinates. The results suggest that when the dominant right arm is used in learning dynamics, the information could be represented in the left hemisphere with neural elements tuned to both the right arm and the left arm. In contrast, learning with the nondominant arm seems to rely on the elements in the nondominant hemisphere tuned only to movements of that arm.

Adolescent↗

Kallikrein 4 is a predominantly nuclear protein and is overexpressed in prostate cancer.

Kallikreins (KLKs) are highly conserved serine proteases that play key roles in a variety of physiological and pathological processes. KLKs are secreted proteins that have extracellular substrates and function. For example, prostate-specific antigen (or KLK3) is a secreted protein that is widely used as a diagnostic marker for prostate cancer. KLK4 is a recently identified member of the kallikrein family that is regulated by androgens and is highly specific to prostate for expression. Here, we show that the gene product of KLK4, hK4, is the first member of the KLK family that is intracellularly localized. We provide strong evidence that the previously assigned first exon that was predicted to code for a signal peptide that would target hK4 for secretion is not part of the physiologically relevant form of KLK4 mRNA. In addition to detailed mapping of the KLK4 mRNA 5' end by RT-PCR, this conclusion is supported by predominantly nuclear localization of the hK4 protein in the cell, documented by both immunofluorescence and cell fractionation experiments. Furthermore, in addition to androgens, hK4 expression is regulated by estrogen and progesterone in prostate cancer cells. Finally, in situ hybridization on normal and hyperplastic prostate samples in tissue microarrays indicate that KLK4 is predominantly expressed in the basal cells of the normal prostate gland and overexpressed in prostate cancer. These data suggest that KLK4 has a unique structure and function compared with other members of the KLK family and may have a role in the biology and characterization of prostate cancer.

Animals↗

Cloning and characterization of KPL2, a novel gene induced during ciliogenesis of tracheal epithelial cells.

To identify genes upregulated during the process of ciliated cell differentiation of airway epithelial cells, differential display was used to compare RNA from rat tracheal epithelial (RTE) cells cultured under conditions that inhibit/promote ciliated cell differentiation. Several partial complementary DNAs (cDNAs) were identified whose expression was regulated coordinately with ciliated cell differentiation. One of these, KPL2, detected a messenger RNA transcript of approximately 6 kb when used as a probe on Northern blots of RNA from ciliated cultures but was undetectable in RNA from nonciliated cultures. Sequencing of overlapping clones obtained by a modified rapid amplification of cDNA ends procedure generated a complete cDNA sequence that exhibited no significant homology to sequences in GenBank, indicating that KPL2 is a novel gene. Southern analysis demonstrated that KPL2 exists as a single-copy gene. KPL2 contains a long open reading frame predicted to code for a protein of > 200 kD. Several putative functional motifs are present in the protein, including a calponin homology domain, three nuclear localization signals, a consensus P-loop, and a proline-rich region, suggesting that KPL2 has a unique function. KPL2 was undetectable in heart and liver samples, but was expressed in brain and testis, tissues that contain axonemal structures. In seminiferous tubules of the testis, KPL2 expression was stage-specific and appeared to be highest in spermatocytes and round spermatids. During differentiation of RTE cells, the expression of KPL2 closely paralleled that of an axonemal dynein heavy chain. These results suggest that KPL2 plays an important role in the differentiation or function of ciliated cells in the airway.

Amino Acid Sequence↗

Molecular cloning and expression of rat lung carboxylesterase and its potential role in the detoxification of organophosphorus compounds.

The 1,839-base pair complementary DNA (cDNA) for rat lung carboxylesterase was cloned by reverse transcriptase polymerase chain reaction from total rat lung RNA using specific primers derived from the 5' and 3' untranslated regions of rat hepatic cholesteryl ester hydrolase (CEH). The unique cDNA was sequenced and found to be similar to hepatic CEH, pI 6.1 esterase, and hydrolase A. In Northern blot analysis, the cDNA hybridized with a single band from lung messenger RNA (mRNA). The 1.7-kb coding sequence, predicting a 62-kD protein, was transfected into COS-7 cells and Chinese hamster ovary (CHO) cells. Expression in COS-7 and CHO cells was accompanied by 4- and 3.2-fold increases in carboxylesterase activity (hydrolysis of p-nitrophenyl acetate), respectively. Unlike the hepatic CEH, the expressed lung carboxylesterase described here did not hydrolyze cholesterol esters. In situ hybridization experiments localized the lung carboxylesterase mRNA to the airway epithelium. The organophosphorus compound phosphoric acid diethyl 4-nitrophenyl ester, paraoxon, completely inhibited this lung carboxylesterase, placing it in the family of B esterases by this criterion.

Amino Acid Sequence↗

Annotation, submission and screening of repetitive elements in Repbase: RepbaseSubmitter and Censor.

BACKGROUND: Repbase is a reference database of eukaryotic repetitive DNA, which includes prototypic sequences of repeats and basic information described in annotations. Updating and maintenance of the database requires specialized tools, which we have created and made available for use with Repbase, and which may be useful as a template for other curated databases. RESULTS: We describe the software tools RepbaseSubmitter and Censor, which are designed to facilitate updating and screening the content of Repbase. RepbaseSubmitter is a java-based interface for formatting and annotating Repbase entries. It eliminates many common formatting errors, and automates actions such as calculation of sequence lengths and composition, thus facilitating curation of Repbase sequences. In addition, it has several features for predicting protein coding regions in sequences; searching and including Pubmed references in Repbase entries; and searching the NCBI taxonomy database for correct inclusion of species information and taxonomic position. Censor is a tool to rapidly identify repetitive elements by comparison to known repeats. It uses WU-BLAST for speed and sensitivity, and can conduct DNA-DNA, DNA-protein, or translated DNA-translated DNA searches of genomic sequence. Defragmented output includes a map of repeats present in the query sequence, with the options to report masked query sequence(s), repeat sequences found in the query, and alignments. CONCLUSION: Censor and RepbaseSubmitter are available as both web-based services and downloadable versions. They can be found at http://www.girinst.org/repbase/submission.html (RepbaseSubmitter) and http://www.girinst.org/censor/index.php (Censor).

Animals↗

Conservation of long-range synteny and microsynteny between the genomes of two distantly related nematodes.

BACKGROUND: Comparisons between the genomes of the closely related nematodes Caenorhabditis elegans and Caenorhabditis briggsae reveal high rates of rearrangement, with a bias towards within-chromosome events. To assess whether this pattern is true of nematodes in general, we have used genome sequence to compare two nematode species that last shared a common ancestor approximately 300 million years ago: the model C. elegans and the filarial parasite Brugia malayi. RESULTS: An 83 kb region flanking the gene for Bm-mif-1 (macrophage migration inhibitory factor, a B. malayi homolog of a human cytokine) was sequenced. When compared to the complete genome of C. elegans, evidence for conservation of long-range synteny and microsynteny was found. Potential C. elegans orthologs for II of the 12 protein-coding genes predicted in the B. malayi sequence were identified. Ten of these orthologs were located on chromosome I, with eight clustered in a 2.3 Mb region. While several, relatively local, intrachromosomal rearrangements have occurred, the order, composition, and configuration of two gene clusters, each containing three genes, was conserved. Comparison of B. malayi BAC-end genome survey sequence to C. elegans also revealed a bias towards intrachromosome rearrangements. CONCLUSIONS: We suggest that intrachromosomal rearrangement is a major force driving chromosomal organization in nematodes, but is constrained by the interdigitation of functional elements of neighboring genes.

Amino Acid Sequence↗

A novel nonsense mutation in CACNA1A causes episodic ataxia and hemiplegia.

OBJECTIVE: To identify the disease-causing mutation and to characterize penetrance and phenotypic variability in a large pedigree with episodic ataxia type 2 (EA-2) previously linked to chromosome 19. BACKGROUND: Mutations in the CACNA1A gene on chromosome 19 encoding a calcium channel subunit cause EA-2, which is characterized by recurrent attacks of imbalance with interictal eye movement abnormalities. METHODS: The authors used single-strand conformation polymorphism (SSCP) analysis to screen for point mutations, and direct sequencing to identify mutations in CACNA1A. Allele-specific oligonucleotides were designed to detect the presence of the diseased allele in members of their pedigree as well as in normal control subjects. RESULTS: Reassessment of members of the pedigree revealed two notable clinical features. Diffuse weakness during attacks of ataxia was a prominent complaint. Two affected individuals had had episodic hemiplegia, one with typical migraine headaches. SSCP analysis revealed aberrant bands in exon 29 in affected members but not in normal control subjects. Direct sequencing of exon 29 identified a C-to-T change at position 4914 of the coding sequence of CACNA1A, predicting an early stop code at codon 1547. Two asymptomatic mutation carriers demonstrated the incomplete penetrance of this mutation. CONCLUSIONS: A nonsense mutation in CACNA1A causes episodic ataxia and complaint of weakness, and may be associated with hemiplegia.

Adolescent↗

Sky-radiance measurements for ocean-color calibration-validation.

The calibration of an ocean-color sensor or validation of water products is generally based on ground-based extinct measurements from which the aerosol products (optical thickness tau(a) and aerosol type) are deduced. Sky-radiance measurements complement the extinction measurements mainly in the aerosol-model characterization. Our basic goal is to promote calibration-validation activities based on the radiative properties of the aerosols rather than their chemical or physical properties. A simple method is proposed (and evaluated) to convert sky radiances measured in the principal plane into atmospheric phase functions P. Indeed tau(a) and P are the required inputs to a radiative-transfer code for predicting the top-of-the-atmosphere radiances. The overall error in this prediction is a few percent. This method can operate on a worldwide network on ground-based sun radiometers and then be used to achieve a statistical analysis for validating satellite products.

Journal Article↗

Menin mutations in patients with multiple endocrine neoplasia type 1.

Multiple endocrine neoplasia type 1 (MEN-1) is a familial cancer syndrome with parathyroid, pituitary and enteropancreatic tumors. The disease phenotype segregates with markers on chromosome 11q13. Very recently a new gene was cloned from this region and was found to carry mutations in 14 of 15 unrelated MEN-1 patients. The gene was termed menin and is predicted to code for a tumor suppressor protein of 610 amino acids, but its precise function is totally unknown. To confirm this finding we used PCR from genomic DNA and direct sequencing to analyze exons 2 through 10 of the menin gene in eight patients from four pedigrees with MEN-1 syndrome or an affected relative. We identified four different heterozygous mutations, three of them are novel: one nonsense mutation, one large deletion of 32 bp and two insertions, all of them located in exon 2. Our results confirm that patients with MEN-1 carry mutations in the menin gene.

Adult↗

Novel regulators of kidney development from the tips of the ureteric bud.

Mammalian nephrogenesis depends on the interaction between the ureteric bud and the metanephric mesenchyme. As the ureteric bud undergoes branching and segmentation, the stalks differentiate into the collecting system of the mature kidney, while the tip cells interact with the adjacent cells of the metanephric mesenchyme, inducing their conversion into nephrons. This induction is mediated by secreted factors. For identifying novel mediators, the tips of the ureteric tree were isolated and microarray analyses were performed using manually refined, multistep gene ontology annotations. For identifying conserved factors, two databases were developed, one from mouse E12.5 and one from rat E13.5 ureteric buds. The overlap of mouse and rat data sets yielded 20 different transcripts that were enriched in the ureteric bud compared with metanephric mesenchyme and predicted to code for secreted proteins. Real-time reverse transcriptase-PCR and in situ hybridization confirmed these identifications. One of the genes that was highly specific to the ureteric bud tip was cytokine-like factor 1 (CLF-1). Recombinant CLF-1 in complex with its physiologic ligand, cardiotrophin-like cytokine (CLC), triggered phosphorylation of signal transducer and activator of transcription 3 in mesenchyme, a pathway characteristic of mesenchymal-to-epithelial conversion. Indeed, when applied to isolated rat metanephric mesenchyme, CLF-1/CLC (3 nM) induced mature nephron structures expressing glomerular and tubular markers. These results underline the power of this first comprehensive gene expression analysis of the ureteric bud tip to identify bioactive molecules.

Animals↗