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J Seurinck

Publications and source records attributed to J Seurinck.

At least 19 recordsLinked to original sources
PubMed1999

Isolation of the LEMMI9 gene and promoter analysis during a compatible plant-nematode interaction.

Plant-endoparasitic root-knot nematodes feed on specialized giant cells that they induce in the vascular cylinder of susceptible plants. Although it has been established that a number of plant genes change their expression pattern during giant cell differentiation, virtually no data are available about the mechanisms involved in that change. One possibility is differential promoter recognition by the transcription factor(s) responsible for the expression of specific genes. We have isolated and characterized a genomic clone from tomato containing the promoter region of LEMMI9, one of the few plant genes that have been reported to be highly expressed in galls (predominantly in giant cells). The analysis of transgenic potato plants carrying a LEMMI9 promoter-beta glucuronidase (GUS) fusion has demonstrated that the tomato promoter was activated in Meloidogyne incognita-induced galls in a heterologous system. We have located putative regulatory sequences in the promoter and have found that nuclear proteins from the galls formed specific DNA-protein complexes with the proximal region of the LEMMI9 promoter. The nuclear protein-binding sequence mapped to a region of 111 bp immediately upstream from the TATA box. This region contains a 12-bp repeat possibly involved in the formation of DNA-protein complexes, which might be related to the LEMMI9 transcriptional activation in the giant cells.

Animals↗
PubMed1998

A tobacco flower-specific gene encodes a polyphenol oxidase.

Identification of pistil-expressed genes is an important step in understanding pistil development and function in plant reproduction. A tobacco stigma/style cDNA library was differentially screened and several cDNA clones were isolated. One of these tobacco genes, designated tobP1, is characterized here. TobP1 encodes a protein highly homologous to plant polyphenol oxidases. Northern blot analysis of total RNA extracted from different organs and probed with tobP1 cDNA identified a single transcript that is exclusively present in flower organs (petals, stamens, and predominantly in pistils). The tobP1 gene is co-ordinately regulated during development in pistils and stamens, and is not induced in mature leaves even under stress conditions. TobP1 belongs to a multigene family, as reported for PPO in other plant species.

Amino Acid Sequence↗
PubMed1997

Intron-mediated enhancement of transgene expression in maize is a nuclear, gene-dependent process.

In monocots, transgene expression can be stimulated by over two magnitudes by including an intron in the 5' untranslated region (UTR). The underlying mechanism is presently unknown. Inclusion of the salT intron into the 5' UTR of cat and bar genes stimulated expression of the first gene only, indicating that intron-mediated enhancement of expression (IME) is gene-dependent. Stimulation was associated with increased cat RNA levels, which did not result from a reduced cytoplasmic turnover and were not associated with increased translation. This implies that IME acts in the nucleus. Importantly, the cytoplasmic accumulation of spliced cat transcripts, even with IME, is less than that encoded by the intronless bar gene. As the cat and bar genes were flanked by identical regulatory signals, and the transcripts had a similar cytoplasmic stability it may mean that IME rescues rather than stimulates gene expression.

Cell Nucleus↗
PubMed1997

Nucleotide sequence and characterization of the cryptic Bacillus thuringiensis plasmid pGI3 reveal a new family of rolling circle replicons.

The complete nucleotide sequence of plasmid pGI3 from Bacillus thuringiensis subsp. thuringiensis H1.1. was obtained. Although this 11,365-bp molecule contained at least 11 putative open reading frames (ORFs), extensive database searches did not reveal any homologous sequences with the exception of ORF6, which displayed similarity to the largest ORF of pSTK1, a 1,883-bp cryptic plasmid isolated from Bacillus stearothermophilus. Deletion analysis to determine the pGI3 minimal replicon revealed that ORF6 is the rep gene. Replication occurred via a single-stranded DNA (ssDNA) intermediate, as demonstrated by S1 treatment and Southern hybridization in nondenaturating conditions. Interestingly, however, no homology was found between the pGI3 (ORF6) and pSTK1 (ORF3) rep genes and those from other single-stranded DNA plasmids, nor was there any DNA similarity to the double-strand origins of replication characterized so far, indicating that pGI3 and pSTK1 form another, new family of ssDNA plasmids. PCR analysis revealed that the pGI3 rep gene is largely distributed among B. thuringiensis strains but can also be found in B. cereus and B. mycoides strains, albeit at a lower frequency. Finally, segregation experiments performed with B. subtilis and B. thuringiensis showed that the pGI3 derivatives, including the minimal replicon, were segregationally stable at temperatures suitable for B. thuringiensis growth (<43 degrees C).

Amino Acid Sequence↗
PubMed1996

A Bacillus thuringiensis insecticidal crystal protein with a high activity against members of the family Noctuidae.

The full characterization of a novel insecticidal crystal protein, named Cry9Ca1 according to the revised nomenclature for Cry proteins, from Bacillus thuringiensis serovar tolworthi is reported. The crystal protein has 1,157 amino acids and a molecular mass of 129.8 kDa. It has the typical features of the Lepidoptera-active crystal proteins such as five conserved sequence blocks. Also, it is truncated upon trypsin digestion to a toxic fragment of 68.7 kDa by removal of 43 amino acids at the N terminus and the complete C-terminal half after conserved sequence block 5. The 68.7-kDa fragment is further degraded to a nontoxic 55-kDa fragment. The crystal protein has a fairly broad spectrum of activity against lepidopteran insects, including members of the families Pyralidae, Plutellidae, Sphingidae, and Noctuidae. A 50% lethal concentration of less than 100 ng/cm2 of diet agar was found for diamondback moth, European corn borer, cotton bollworm, and beet armyworm. It is the first insecticidal crystal protein with activity against cutworms. No activity was observed against some beetles, such as Colorado potato beetle. The protein recognizes a receptor different from that recognized by Cry1Ab5 in Ostrinia nubilalis and Plutella xylostella. In Spodoptera exigua and P. xylostella, it binds to a receptor which is also recognized by Cry1Cax but with a lower affinity. In these insects, Cry1Cax probably binds with a higher affinity to an additional receptor which is not recognized by Cry9Ca1. Elimination of a trypsin cleavage site which is responsible for the degradation to a nontoxic fragment did result in protease resistance but not in increased toxicity against O. nubilalis.

Amino Acid Sequence↗
PubMed1995

Characterization and heterologous expression of the tetL gene and identification of iso-ISS1 elements from Enterococcus faecalis plasmid pJH1.

The tetracycline-resistance (TcR) determinant of the Enterococcus faecalis plasmid pJH1 has been identified and located on a 2.2-kb RsaI-EcoRI fragment. The fragment was cloned in Escherichia coli, and specified TcR in this host. The nucleotide (nt) sequence of the cloned fragment showed the presence of an open reading frame (ORF) of 1374 bp, designated tetL. The nt sequence of tetL from pJH1 was identical to that of the tetL present on pLS1 from Streptococcus agalactiae. Upstream of the pJH1 tetL, part of another ORF was found that, except for two single-nt substitutions, was identical to an iso-ISS1 element from Lactococcus lactis. Hybridization studies indicated the presence of several ISS1-like elements in plasmid pJH1, but not on the En. faecalis chromosome. To study its usefulness as a marker in Gram+ organisms, the pJH1 tetL was cloned on the broad-host-range plasmid pNZ124, resulting in pNZ280, that was found to give resistance to 40 micrograms Tc/ml in Lc. lactis and Bacillus subtilis.

Amino Acid Sequence↗
PubMed1995

cry IA(b) transcript formation in tobacco is inefficient.

Chimaeric PCaMV35Scry genes direct in tobacco mesophyll protoplasts mRNA levels of less than one transcript per cell. We provide evidence that this low cytoplasmic cry IA(b) mRNA level is not due to a rapid turnover but rather results from a marginal import flow of cry messenger into the cytoplasm. Run-on assays indicate that the frequency of transcription initiation is not limiting. However, the cry precursor mRNA carries at least three regions that are recognized as introns. The absence of high cytoplasmic levels of spliced cry mRNAs suggests that these mRNAs are unstable and/or not efficiently made. Point mutations in the 5' splice site of the most distal intron allows high accumulation levels of the full-length mRNA. This implies that the inefficient formation of full-size mRNA is a major cause of the low expression level of chimaeric cry IA(b) genes in tobacco.

Bacillus thuringiensis Toxins↗
PubMed1993

Inflorescence-specific genes from Arabidopsis thaliana encoding glycine-rich proteins.

Genomic and cDNA clones for three inflorescence-specific genes from Arabidopsis thaliana were isolated and characterized. The genes are tandemly organized in the genome on a 10 kb fragment. The expression of these genes is coordinately regulated in a developmental and organ-specific pattern. They are expressed predominantly in anthers at the later stage of flower development. The primary structure of the encoded gene products exhibits comparable features consisting of a hydrophobic domain at the N-terminal region followed by repeated glycine-rich motifs. Little homology is observed either between the glycine-rich domain of the three genes or with previously described glycine-rich proteins from other plant species.

Amino Acid Sequence↗
PubMed1993

The 3' untranslated region of satellite tobacco necrosis virus RNA stimulates translation in vitro.

The RNA of satellite tobacco necrosis virus (STNV) is a monocistronic messenger that lacks both a 5' cap structure and a 3' poly(A) tail. We show that in a cell-free translation system derived from wheat germ, STNV RNA lacking the 600-nucleotide trailer is translated an order of magnitude less efficiently than full-size RNA. Deletion analyses positioned the translational enhancer domain (TED) within a conserved hairpin structure immediately downstream from the coat protein cistron. TED enhances translation when fused to a heterologous mRNA, but the level of enhancement depends on the nature of the 5' untranslated sequence and is maximal in combination with the STNV leader. The STNV leader and TED have two regions of complementarity. One of the complementary regions in TED resembles picornavirus box A, which is involved in cap-independent translation but which is located upstream of the coding region.

Base Sequence↗
PubMed1992

Developmental expression of tobacco pistil-specific genes encoding novel extensin-like proteins.

We have sought to identify pistil-specific genes that can be used as molecular markers to study pistil development. For this purpose, a cDNA library was constructed from poly(A)+ RNA extracted from tobacco stigmas and styles at different developmental stages. Differential screening of this library led to the isolation of cDNA clones that correspond to genes preferentially or specifically expressed in the pistil. Seven of these cDNA clones encode proteins containing repetitions of the pentapeptide Ser-Pro4, which is a typical motif found in extensins. Unlike extensin genes, the extensin-like genes described here are not induced under stress conditions. RNA gel blot hybridizations demonstrated the organ-specific expression of the extensin-like genes and their temporal regulation during pistil development. After pollination, the transcript levels of the pistil-specific extensin-like genes change relative to levels in unpollinated pistils. In situ hybridization experiments showed that at least one of these pistil-specific genes is specifically expressed in cells of the transmitting tissue. The possible roles of the extensin-like proteins in pistils are discussed.

Amino Acid Sequence↗
PubMed1991

Structural similarities between the RNAs of two satellites of tobacco necrosis virus.

The complete nucleotide sequence of satellite tobacco necrosis virus 2 (STNV-2) RNA has been determined. It has the same organization as the previously studied STNV-1 RNA. The 5' untranslated regions (about 30 nt) are nearly identical, while the coat protein coding regions (about 600 nt) have 55% nucleotide sequence similarity. The 620-nt-long trailer sequences, with 64% nucleotide sequence conservation, can fold into a phylogenetically conserved secondary structure consisting of three pseudoknots followed by a long-range interaction-born hairpin structure. The significance of these elements is discussed in view of the particular properties (stability, translational competitiveness, and replication) that characterize these RNAs.

Base Sequence↗
PubMed1991

The tobacco luminal binding protein is encoded by a multigene family.

We have cloned cDNAs of the tobacco homolog of the luminal binding protein (BiP) that has been described in other higher eukaryotes. In contrast to the mammalian and yeast protein, tobacco BiP is encoded by a multigene family. The gene products of all the cloned members of this family contain a carboxy-terminal His-Asp-Glu-Leu peptide that may form the signal for retention in the endoplasmic reticulum. Analysis of expression patterns revealed that BiP transcripts are predominantly present in tissues with high rates of cell divisions, in secretory tissues, and in cells treated with tunicamycin. We also show that a chimeric gene containing the coding region of one of the tobacco BiP genes is able to complement a mutation in the Saccharomyces cerevisiae BiP gene.

Amino Acid Sequence↗
PubMed1990

Genome structure of tobacco necrosis virus strain A.

An almost complete sequence of the RNA genome of tobacco necrosis virus (TNV) strain A has been determined. The genome organization is very similar to that of carnation mottle virus (CarMV) and turnip crinkle virus (TCV). The 5'-proximal open reading frame (ORF) encodes a 23-kDa protein and read-through of its amber codon into the second ORF is presumably used for the translation of a 82-kDa protein. The third large ORF encodes the 30-kDa coat protein. Two small ORFs are located upstream and one immediately downstream of this coat protein cistron. Extensive sequence similarity was found between the TNV 82-kDa protein and the putative polymerases of TCV, CarMV, cucumber necrosis virus (CNV), maize chlorotic mottle virus (MCMV), red clover necrotic mosaic virus (RCNMV), and barley yellow dwarf virus (BYDV). The TNV coat protein is very similar to southern bean mosaic virus (SBMV) capsid protein. Of the predicted small proteins only a 7.9-kDa protein shows some sequence similarity with a corresponding protein of MCMV, CarMV, and TCV. The others are unique to TNV. Except for the first four nucleotides at the 5' end no homology was found with the RNA of STNV (satellite of TNV).

Amino Acid Sequence↗
PubMed1990

Differential expression of five Arabidopsis genes encoding glycine-rich proteins.

Five cDNA clones coding for glycine-rich proteins in Arabidopsis thaliana were isolated. The corresponding genes are present in the genome as single copies. The derived protein sequences contain highly repetitive glycine-rich motifs. There is, however, little homology among them, nor with previously described glycine-rich proteins from other species. All five genes are expressed in leaves and stems of 6-week-old plants but show different patterns of expression in other organ systems. Analysis of the effect of different external stimuli on the expression pattern showed that, in most cases, the transcript levels were moderately but selectively affected. With flooding stress, the accumulated level of the transcript from one of the genes was remarkably increased.

Amino Acid Sequence↗