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J A Gatehouse

Publications and source records attributed to J A Gatehouse.

At least 37 records · Page 2Linked to original sources
PubMed1997

Differentially regulated inhibitor-sensitive and insensitive protease genes from the phytophagous insect pest, Helicoverpa armigera, are members of complex multigene families.

Ingestion of soybean Kunitz trypsin inhibitor (SKTI) by larvae of the phytophagous insect pest Helicoverpa armigera induced production of inhibitor-insensitive protease activity. The induced activity was not due to proteolytic enzymes of different mechanistic classes, but rather to variants of the existing enzymes. Characterization of cDNAs showed that sequences encoding proteins of the serine protease family were abundant in gut tissue of both control and SKTI-fed insects. The majority of serine protease family cDNAs encode enzymes closely homologous to trypsin and chymotrypsin; comparison of these sequences shows variation in amino acid residues within the region which would be in contact with a protein protease inhibitor. More diverged sequences which may not encode active proteases are also present. All the cDNAs examined were found to derive from multigene families; at least 28 different genes are present in the serine protease family. Chronic ingestion of SKTI results in some serine protease-encoding mRNA species increasing in level, whereas others decrease. Chymotrypsin-encoding mRNAs tend to increase in level as a result of SKTI ingestion, but no clear trend is shown by trypsin-encoding mRNAs. It is suggested that multiple, varying protease-encoding genes are an adaptive mechanism for reducing the deleterious effects of plant protease inhibitors.

Amino Acid Sequence↗
PubMed1997

A 38 bp repeat sequence within the pea seed storage protein promoter of legA is a binding site for a nuclear DNA-binding protein.

This paper describes a target sequence for a pea seed nuclear DNA-binding protein (of Pisum sativum) present at the cell expansion phase. Electromobility shift assays as well as in situ copper-phenanthroline footprinting have shown that this protein binds to an imperfect repeat sequence of the legA promoter located -404 tot -367 relative to the transcriptional start site, a region designated USR1 (-549 tot -316). Competition assays showed that the same or a related protein binds to USR2 located at -833 to -582. Another protein that does not recognize the repeat sequence as a target site binds adjacent but upstream to the repeat sequence in USR1. It is suggested that these protein-DNA interactions are initial events in the assembly of a transcriptional activation complex.

Base Composition↗
PubMed1997

Characterisation of a pea hsp70 gene which is both developmentally and stress-regulated.

A pea pod cDNA library was screened for sequences specific to lignifying tissue. A cDNA clone (pLP19) encoding the C-terminal region of a hsp70 heat shock protein hybridised only to pod mRNA from pea lines where pod lignification occurred. Expression of pLP19 was induced by heat shock in leaves, stems and roots of pea and chickpea plants. Four different poly(A) addition sites were observed in cDNAs derived from the same gene as pLP19. This gene was fully sequenced; unlike most hsp70 genes, it contains no introns. The 5'-flanking sequence contains heat shock elements and other potential regulatory sequences.

Amino Acid Sequence↗
PubMed1994

Characterization and sequencing of cDNA clone encoding the phloem protein PP2 of Cucurbita pepo.

Direct N-terminal amino acid sequencing of the phloem protein 2 (PP2) from 3-month old Cucurbita pepo L. (pumpkin), purified by SDS-PAGE and blotted onto PVDF membrane, showed that the protein had a blocked N-terminus. However, after in situ cleavage of the polypeptide in a gel slice by cyanogen bromide, 75 residues of sequences on two cyanogen bromide fragments were determined. An oligonucleotide probe based on this amino acid sequence was used to screen a cDNA library, constructed from mRNA of 3-5-day old seedling hypocotyls, in lambda ZAP II. A cDNA clone (p11A) predicted an amino acid sequence of 218 residues, in full agreement with the sequences determined for two CNBr fragments of PP2, and suggests that the N-terminus of the protein is a blocked methionine residue which is cleaved off by CNBr. Two additional cDNA clones were sequenced but no heterogeneity in the PP2 sequence was found. The deduced amino acid sequence of C. pepo differs in nine residues from the recently published sequence of Cucurbita maxima (Bostwick et al., Plant Cell 4 (1992) 1539-1548). Southern blot showed that PP2 is encoded by a gene family with a relatively large number of members (estimated as 7-15 per haploid genome).

Amino Acid Sequence↗
PubMed1993

Characterisation of potato (Solanum tuberosum L.) extensins: a novel extensin-like cDNA from dormant tubers.

A cDNA library from dormant potato tubers was screened for extensin (Ext)-like cDNAs (PTEL). The cDNAs recovered were partially sequenced and could be divided into two classes. One class, containing the repeating amino acid (aa) motifs, SPPPPSPKYVYK and SPPPPSPSPPPPYYYK, constitutes the potato counterpart of the tomato Ext-encoding gene previously isolated by Zhou et al. [Plant Mol. Biol. 20 (1992) 5-17]. A full-length cDNA from the second class was fully sequenced. The product of this cDNA has the repetitive sequence and proline-rich composition typical of Ext. Features worthy of note are the signal peptide sequence, which shares close homology with signal sequences of a number of Ext of diverse origin, and the presence of a novel, histidine-rich motif (SPPPHHHHPVYK) repeated within the sequence. Wounding of the potato tuber causes a marked increase in Ext-like mRNAs, although the species induced are not those present in dormant tissue.

Amino Acid Sequence↗
PubMed1993

Sequence of a novel plant ras-related cDNA from Pisum sativum.

A clone isolated from a purple podded pea (Pisum sativum L.) cDNA library was shown to contain the complete coding sequence of a polypeptide with considerable homology to various members of the ras superfamily. The ras superfamily are a group of monomeric GTP-binding proteins of 21-25 kDa found in eukaryotic cells. Conserved sequences in the isolated clone include the GTP-binding site, GDP/GTP hydrolysis domain and C-terminal Cys residues involved in membrane attachment. Comparisons of the predicted amino acid sequence with those of other ras proteins show significantly higher homologies (ca. 70%) to two mammalian gene products, those of the BRL-ras oncogene, and the canine rab7 gene, than to any of the plant ras gene products so far identified (< 40% homology). The high percentage of amino acid identity suggests that this cDNA may be the product of a gene, designated Psa-rab, which is the plant counterpart of rab7. Rab/ypt proteins are a subfamily of the ras superfamily thought to be involved in intracellular transport from the endoplasmic reticulum to the Golgi apparatus and in vesicular transport. Northern blot hybridisation analysis of total RNA from green and purple podded pea revealed a mRNA species of approximately the same size as the isolated cDNAs.

Amino Acid Sequence↗
PubMed1992

A complete sequence of the rice sucrose synthase-1 (RSs1) gene.

Using a fragment of the maize sucrose synthase gene Sh-1 as probe, the rice genome was shown to contain at least three genes encoding sucrose synthase. One of these genes was isolated from a genomic library, and its full sequence, including 1.7 kb of 5' flanking sequence and 0.9 kb of 3' flanking sequence, is reported. The new rice gene, designated RSs1, is highly homologous to maize Sh-1 (approx. 94% identity in derived amino acid sequence), and contains an identical intron-exon structure (16 exons and 15 introns). Both RSs1 and maize Sh-1 show similar sequence homologies to a second rice sucrose synthase gene described recently (designated RSs2, Yu et al. (1992) Plant Mol Biol 18: 139-142), although both the rice genes predict an extra 6 amino acids at the C-terminus of the protein when compared to the maize gene. The RSs1 5' flanking sequence contains a number of promoter-like sequences, including putative protein-binding regions similar to maize zein genes.

Amino Acid Sequence↗
PubMed1992

Expression of the pea metallothionein-like gene PsMTA in Escherichia coli and Arabidopsis thaliana and analysis of trace metal ion accumulation: implications for PsMTA function.

The PsMTA gene from pea (Pisum sativum) shares similarity with metallothionein (MT) genes and related sequences have also been isolated from a number of other higher-plant species. The proteins encoded by these genes have not yet been purified from plants and their functions remain unclear although, by analogy to MT, roles in the metabolism and detoxification of metal ions have been proposed. By contrast, correlation between transcript abundance and Fe availability has led to an alternative proposal that these genes are involved in mechanisms of Fe efficiency. Phenotypic effects of constitutive PsMTA expression were examined in Escherichia coli and Arabidopsis thaliana. Copper accumulation by E. coli cells expressing recombinant PsMTA protein was approximately 8-fold greater than in control cells. No significant effects on the accumulation of Zn or Cd were detected. In segregating A. thaliana progeny, derived from a transgenic F1 parent containing the PsMTA gene under the control of a CaMV 35S promoter, 75% of individuals accumulated more Cu (several-fold in some plants) than untransformed, control plants. These data suggest that PsMTA protein binds Cu in planta and that uncoupled (constitutive) expression of the PsMTA gene causes enhanced Cu accumulation. Roots of P. sativum plants grown under conditions of low Fe availability showed elevated activity of root surface Fe(III) reductase and accumulated more Cu than roots of plants grown in an Fe-supplemented solution. Changes in the expression of MT-like genes, coincident with changes in Fe availability, are consistent with a role in Cu homoeostasis.

Arabidopsis↗
PubMed1990

A gene from pea (Pisum sativum L.) with homology to metallothionein genes.

While searching for 'organ-specific' genes in pea (Pisum sativum L.) we have isolated a gene (designated PsMTA) which has an ORF encoding a predicted protein with some similarity to metallothioneins (MTs). The PsMTA transcript is abundant in roots which have not been exposed to elevated concentrations of trace metals.

Amino Acid Sequence↗
PubMed1990

Sequences 5' to the conserved 28 bp Leg box element regulate the expression of pea seed storage protein gene legA.

The function of the 28 bp conserved Leg box element found in the 11S legumin-like genes of Vicia, Pisum, Glycine and Helianthus in controlling gene expression has been examined. Transgenic tobacco plants containing 124 bp of 5' legA flanking sequence including the Leg box and all sequences downstream to the start of transcription failed to activate the gene, as judged by ELISA and northern assays. Expression was first detected in a promoter truncation construct which contained 549 bp of 5' flanking sequence. These two promoter truncation constructs were additionally examined for their ability to interact with pea seed nuclear proteins. The use of DNA-protein binding and mobility shift assays showed that the -124 bp fragment which included the Leg box did not bind nuclear proteins. In contrast, nuclear proteins were shown to strongly bind to the -549 bp flanking sequence fragment. The correlation of transgenic plant analysis with DNA binding assays indicates that the highly conserved 28 bp Leg box element is not the sole promoter determinant in legumin gene expression.

Base Sequence↗
PubMed1990

The extensin gene family in oilseed rape (Brassica napus L.): characterisation of sequences of representative members of the family.

A family of cross-hybridising cDNA clones has been isolated from a cDNA library produced with poly(A)+ RNA from the roots of oilseed-rape (Brassica napus L.). The clones were selected as abundantly expressed in root by differential screening of the root cDNA library with cDNA probes prepared from root, green leaf, etiolated leaf and developing seed. mRNA species corresponding to the selected abundant clones were expressed in roots at levels of at least 400 times those in other organs, as shown by Northern blot analysis and RNase protection assays. Complete nucleotide sequence determination of the cDNA clones showed that they encoded proteins homologous to carrot extensin and were the products of at least three different genes. An extensin gene, designated extA, was obtained from an oilseed rape (B. napus L.) genomic library screened with a cDNA species encoding a protein expressed abundantly in roots. The gene is a member of a multigene family, consisting of about 3 members per haploid genome with strong homology to the probe, and a further 20 or so members with weaker homology. The isolated gene, although not identical to the cDNA probe, was also found to be specifically expressed in roots, and was transcribed into a mRNA species approximately 1,300 nucleotides in size. A single transcription start was identified by S1 mapping. The complete nucleotide sequence of the extA gene and its flanking regions has been determined and shown to encode a protein homologous to carrot and tomato extensins.

Amino Acid Sequence↗
PubMed1990

A cDNA encoding an S-locus specific glycoprotein from Brassica oleracea plants containing the S5 self-incompatibility allele.

A cDNA sequence homologous to the Brassica self-incompatibility locus specific glycoprotein (SLSG) sequence was isolated from stigmas of B. oleracea plants homozygous for the S5 allele. The nucleotide sequence of this cDNA was obtained and compared with the S6 allelic form of the SLSG. Evidence is presented which indicates that this sequence does not specify the self-incompatibility response of pollen.

Alleles↗
PubMed1989

Protein and cDNA sequences of Bowman-Birk protease inhibitors from the cowpea (Vigna unguiculata Walp.).

The protein and gene sequences of the cowpea Bowman-Birk type trypsin inhibitor which confers enhanced insect resistance to transgenic tobacco plants, and of cowpea trypsin/chymotrypsin inhibitors are presented. There are regions of high conservation and high divergence within the 5' leader, mature protein and 3' non-coding regions of the Bowman-Birk inhibitors and in the genes which encode them in different members of this family within the Leguminosae. The practical implications of this finding for studies on the evolution of plants and the utilization of these genes for enhancing insect resistance is discussed.

Amino Acid Sequence↗
PubMed1988

The sequence of a gene encoding convicilin from pea (Pisum sativum L.) shows that convicilin differs from vicilin by an insertion near the N-terminus.

The sequence of a gene encoding convicilin, a seed storage protein in pea (Pisum sativum L.), is reported. This gene, designated cvcA, is one of a sub-family of two active genes. The transcription start of cvcA was mapped. Convicilin genes are expressed in developing pea seed cotyledons, with maximum levels of the corresponding mRNA species present at 16-18 days after flowering. The gene sequence shows that convicilin is similar to vicilin, but differs by the insertion of a 121-amino-acid sequence near the N-terminus of the protein. This inserted sequence is very hydrophilic and has a high proportion of charged and acidic residues; it is of a similar amino acid composition to the sequences found near the C-terminal of the alpha-subunit in pea legumin genes, but is not directly homologous with them. Comparison of this sequence with the 'inserted' sequence in soya-bean (Glycine max) conglycinin (a homologous vicilin-type protein) suggests that the two insertions were independent events. The 5' flanking sequence of the gene contains several putative regulatory elements, besides a consensus promoter sequence.

Amino Acid Sequence↗
PubMed1988

Isolation and expression of a pea vicilin cDNA in the yeast Saccharomyces cerevisiae.

A cDNA clone containing the complete coding sequence for vicilin from pea (Pisum sativum L.) was isolated. It specifies a 50,000-Mr protein that in pea is neither post-translationally processed nor glycosylated. The cDNA clone was expressed in yeast from a 2 micron plasmid by using the yeast phosphoglycerate kinase promoter and initiator codon. The resultant fusion protein, which contains the first 16 amino acid residues of phosphoglycerate kinase in addition to the vicilin sequence, was purified and subsequently characterized. It has slightly slower mobility on SDS/polyacrylamide-gel electrophoresis than standard pea vicilin and forms a mixture of multimers, some of which resemble the native protein.

Amino Acid Sequence↗
PubMed1988

Two genes encoding 'minor' legumin polypeptides in pea (Pisum sativum L.). Characterization and complete sequence of the LegJ gene.

A genomic clone from pea (Pisum sativum L.) contains all of one gene encoding a 'minor' (B-type) legumin polypeptide, and most of a second very similar gene. The two genes, designated LegJ and LegK, are arranged in tandem, separated by approx. 6 kb. A complete sequence of gene LegJ and its flanking sequences is given, with as much of the sequence of gene LegK as is present on the genomic clone. Hybridization of 3' flanking sequence probes to seed mRNA, and sequence comparisons with cDNA species, suggested that gene LegJ, and probably gene LegK, was expressed. The partial amino acid sequences of 'minor' legumin alpha- and beta-polypeptides were used to confirm the identity of these genes. The transciption start in gene LegJ was mapped. The 5' flanking sequence of gene LegJ contains a sequence conserved in legumin genes from pea and other species, which is likely to have functional significance in control of gene expression. Sequence comparisons with legumin genes and cDNA species from Vicia faba and soya bean show that separation of legumin genes into A- and B-type subfamilies occurred before separation of the Viciae and Glycinae tribes.

Base Sequence↗
PubMed1985

Regulation of storage-protein synthesis in pea (Pisum sativum L.) cotyledons under conditions of sulphur deficiency.

The effects of sulphur deficiency on the expression of storage-protein genes in developing pea (Pisum sativum) cotyledons were studied. Legumin-gene transcription was decreased by S-deficiency, but not to the same extent as the decrease in the level of legumin mRNA. Vicilin-gene transcription was not significantly affected. Control of gene expression may thus occur during transcription and/or post-transcriptional events.

Cell Nucleus↗