Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Genes, Insect”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 793 records · Page 44Linked to original sources
PubMed2002

Interaction of gene-cloned and insect cell-expressed aminopeptidase N of Spodoptera litura with insecticidal crystal protein Cry1C.

Insecticidal toxins produced by Bacillus thuringiensis interact with specific receptors located in the midguts of susceptible larvae, and the interaction is followed by a series of biochemical events that lead to the death of the insect. In order to elucidate the mechanism of action of B. thuringiensis toxins, receptor protein-encoding genes from many insect species have been cloned and characterized. In this paper we report the cloning, expression, and characterization of Cry toxin-interacting aminopeptidase N (APN) isolated from the midgut of a polyphagous pest, Spodoptera litura. The S. litura APN cDNA was expressed in the Sf21 insect cell line by using a baculovirus expression system. Immunofluorescence staining of the cells revealed that the expressed APN was located at the surface of Sf21 cells. Treatment of Sf21 cells expressing S. litura APN with phosphatidylinositol-specific phospholipase C demonstrated that the APN was anchored in the membrane by a glycosylphosphatidylinositol moiety. Interaction of the expressed receptor with different Cry toxins was examined by immunofluorescence toxin binding studies and ligand blot and immunoprecipitation analyses. By these experiments we showed that the bioactive toxin, Cry1C, binds to the recombinant APN, while the nonbioactive toxin, Cry1Ac, showed no interaction.

Amino Acid Sequence↗
PubMed1998

Analysis of a mosquito acetylcholinesterase gene promoter.

Insect acetylcholinesterase is the target site for organophosphorus and carbamate insecticides and point mutations in the Ace gene are associated with resistance in Drosophila melanogaster and Musca domestica. However, little is known of the genetic regulation of insect Ace genes. Here we report the isolation of four different cDNAs from an Aedes Ace locus and identification of the gene promoter. Northern analysis reveals two large (>10 kb) transcripts and one smaller transcript of 4 kb. The region containing the initiation of transcription was localized by sequencing the two 5' most cDNAs and by 5' RACE. The transcription start point was subsequently identified by primer extension and is flanked by a perfect arthropod initiator consensus sequence. The promoter lacks a TATA box but contains several matches to other consensus sequences for eukaryotic transcription factors. In common with the Drosophila Ace gene, there are also multiple potential initiators of translation (ATGs) upstream of the main open reading frame. The structure of the 5' leader and promoter is compared to that found in other insect and vertebrate Ace genes and the possibility that this locus is homologous to one of two Ace loci described in another mosquito, Culex pipiens, is discussed.

Acetylcholinesterase↗
PubMed1995

Trans-sialidase genes expressed in mammalian forms of Trypanosoma cruzi evolved from ancestor genes expressed in insect forms of the parasite.

The trans-sialidase of Trypanosoma cruzi mammalian forms transfers sialic acids from host's cell-surface glycoconjugates to acceptor molecules on parasite cell surface. To investigate the mechanism by which the mammalian stages of Trypanosoma cruzi have acquired their trans-sialidase, we compared the nucleotide and predicted amino acid sequences of trans-sialidase genes expressed in different developmental stages and strains of Trypanosoma cruzi with the sialidase gene of Trypanosoma rangeli and the sialidase genes of the prokaryotic genera Clostridium, Salmonella, and Actinomyces. The trans-sialidase gene products of Trypanosoma cruzi have a significant degree of structural and biochemical similarity to the sialidases found in bacteria and viruses, which would hint that horizontal gene transfer occurred in Trypanosoma cruzi trans-sialidase evolutionary history. The comparison of inferred gene trees with species trees suggests that the genes encoding the T. cruzi trans-sialidase of mammalian forms might be derived from genes expressed in the insect forms of the genus Trypanosoma. The branching order of trees inferred from T. cruzi trans-sialidase sequences, the sialidase from Trypanosoma rangeli, and bacterial sialidases parallels the expected branching order of the species and suggests that the divergence times of these sequences are remarkably long. Therefore, a "vertical" inheritance from a hypothetical eukaryotic trans-sialidase gene expressed in insect forms of trypanosomes is more likely to have occurred than the horizontal gene transfer from bacteria, and thus explains the presence of this enzyme in the mammalian infective forms of Trypanosoma cruzi.

Amino Acid Sequence↗
PubMed2007

The insect metalloproteinase inhibitor gene of the lepidopteran Galleria mellonella encodes two distinct inhibitors.

The insect metalloproteinase inhibitor (IMPI) from the greater wax moth, Galleria mellonella, represents the first and to date only specific inhibitor of microbial metalloproteinases reported from animals. Here, we report on the characterization including carbohydrate analysis of two recombinant constructs encoded by impi cDNA either upstream or downstream of the furin cleavage site identified. rIMPI-1, corresponding to native IMPI purified from hemolymph, is encoded by the N-terminal part of the impi sequence, whereas rIMPI-2 is encoded by its C-terminal part. rIMPI-1 is glycosylated at N48 with GlcNAc2Man3, showing fucosylation to different extents. Similarly, rIMPI-2 is glycosylated at N149 with GlcNAc2Man3, but is fully fucosylated. rIMPI-1 represents a promising template for the design of second-generation antibiotics owing to its specific activity against thermolysin-like metalloproteinases produced by human pathogenic bacteria such as Vibrio vulnificus. In contrast, rIMPI-2 does not inhibit bacterial metalloproteinases, but is moderately active against recombinant human matrix metalloproteinases (MMPs). Both microbial metalloproteinases and MMPs induce expression of the impi gene when injected into G. mellonella larvae. These findings provide evidence that the impi gene encodes two distinct inhibitors, one inhibiting microbial metalloproteinases and contributing to innate immunity, the other putatively mediating regulation of endogenous MMPs during metamorphosis.

Amino Acid Sequence↗
PubMed1993

A functional analysis of the P-element gene-transfer vector in insects.

A P-element mobility excision assay was used to determine if non-drosophilid insects could support P gene vector function. Present studies included the testing of Muscids, Sphaerocerids, and Phorids, none of which were able to support P mobility. A new excision indicator plasmid was developed allowing the detection and recovery of virtually all P-element excision products. The frequency and sequence analysis of excision products from Drosophila melanogaster and another drosophilid, Chymomyza procnemis, indicated both quantitative and qualitative differences in the activity of transposase. The quantitative relationships observed in the original assay were maintained, and qualitative differences in transposase activity were reflected in the sequence of the empty donor sites. The results suggest that host factors are involved in cutting and ligating P-element DNA during excision, with transposase facilitating these processes. Possible limitations on P mobility by abnormal transposase transcript processing were tested in Anastrepha suspensa using transposase-encoding plasmids having deleted intron sequences. A transposase cDNA supported normal P excision in D. melanogaster, and a low level of mobility in A. suspensa. Possible applications of gene transfer in insects are presented, in particular methods to genetically sterilize and sex insects for the sterile-insect technique.

Animals↗
PubMed1996

The insect cytochrome oxidase I gene: evolutionary patterns and conserved primers for phylogenetic studies.

Insect mitochondrial cytochrome oxidase I (COI) genes are used as a model to examine the within-gene heterogeneity of evolutionary rate and its implications for evolutionary analyses. The complete sequence (1537 bp) of the meadow grasshopper (Chorthippus parallelus) COI gene has been determined, and compared with eight other insect COI genes at both the DNA and amino acid sequence levels. This reveals that different regions evolve at different rates, and the patterns of sequence variability seems associated with functional constraints on the protein. The COOH-terminal was found to be significantly more variable than internal loops (I), external loops (E), transmembrane helices (M) or the NH2 terminal. The central region of COI (M5-M8) has lower levels of sequence variability, which is related to several important functional domains in this region. Highly conserved primers which amplify regions of different variabilities have been designed to cover the entire insect COI gene. These primers have been shown to amplify COI in a wide range of species, representing all the major insect groups; some even in an arachnid. Implications of the observed evolutionary pattern for phylogenetic analysis are discussed, with particular regard to the choice of regions of suitable variability for specific phylogenetic projects.

Amino Acid Sequence↗
PubMed2002

Molecular cloning and initial characterization of the MG61/PORC gene, the human homologue of the Drosophila segment polarity gene Porcupine.

Insect and vertebrate Porcupine genes encode multi-pass endoplasmic reticulum proteins involved in the processing of Wnt (wingless and int homologue) proteins, a class of secreted glycoprotein factors homologous to the Drosophila melanogaster segment polarity gene Wingless (Wg). Here we report the cloning of cDNAs encoding the human homologue of the Drosophila gene Porcupine (Porc), the characterization of its genomic structure and the quantitative analysis of its expression in a comprehensive panel of human tissues. The human Porcupine locus (MG61/PORC) spans 15 exons over approximately 12 kb of genomic sequence on Xp11.23. Real-time quantitative expression analysis reveals that MG61/PORC transcripts are expressed in multiple tissues, but are particularly abundant in the brain. Like its mouse and Xenopus homologues, MG61/PORC encodes four protein isoforms (A-D) generated through alternative splicing and expressed in a tissue-specific fashion. Finally, we present evidence indicating that MG61/PORC can influence the activity of a human Wnt7A expression construct in a T-cell factor-responsive reporter assay.

Acyltransferases↗
PubMed2005

Metal-responsive transcription factor (MTF-1) handles both extremes, copper load and copper starvation, by activating different genes.

From insects to mammals, metallothionein genes are induced in response to heavy metal load by the transcription factor MTF-1, which binds to short DNA sequence motifs, termed metal response elements (MREs). Here we describe a novel and seemingly paradoxical role for MTF-1 in Drosophila in that it also mediates transcriptional activation of Ctr1B, a copper importer, upon copper depletion. Activation depends on the same type of MRE motifs in the upstream region of the Ctr1B gene as are normally required for metal induction. Thus, a single transcription factor, MTF-1, plays a direct role in both copper detoxification and acquisition by inducing the expression of metallothioneins and of a copper importer, respectively.

Animals↗
PubMed1994

A common multiple cloning site in a set of vectors for expression of eukaryotic genes in mammalian, insect and bacterial cells.

Here, we describe the construction of plasmid vectors facilitating expression of cloned genes in bacteria and in cells of mammalian and insect origin. Two types of multiple cloning site (MCS) were designed based on the MCS in the expression vector lambda gt11Sfi-Not. In the first set of vectors a start Met codon was included in the same reading frame as in lambda gt11Sfi-Not to support expression of partial cDNA clones. Thus a cDNA insert of lambda gt11Sfi-Not could be shuttled among the new vectors for expression. The other set of vectors without a start codon were suitable for expression of cDNA carrying their own start Met codon. By Western blot analysis and by transactivation of a reporter plasmid in co-transfections we show that cDNA is very efficiently expressed in NIH 3T3 cells under control of the elongation factor 1 alpha promoter.

3T3 Cells↗
PubMed1992

A cellular promoter-based expression cassette for generating recombinant baculoviruses directing rapid expression of passenger genes in infected insects.

We have developed an expression cassette which allows the generation of recombinant baculoviruses that can express passenger genes under the control of a constitutive cellular promoter derived from the cytoplasmic actin gene of the silkmoth Bombyx mori. Silkmoth tissue culture cells which were infected with a recombinant B. mori nuclear polyhedrosis virus (BmNPV) containing the gene-encoding chloramphenicol acetyltransferase (CAT) under the control of this expression cassette expressed significant CAT activity beginning 5 hr postinfection (p.i.). Cells infected with a recombinant BmNPV containing the cat gene under the control of the polyhedrin gene promoter did not express CAT activity until 20 hr p.i. Silkworm larvae were also infected with the two recombinant viruses by hemocelic injections and all larval tissues examined were found to express the cat gene. While significant actin-cassette-driven CAT expression in vivo was first seen at 24 hr p.i., expression from the polyhedrin promoter was not seen until 48 hr p.i. By 60 hr p.i., tissues of larvae infected with the recombinant virus expressing cat under polyhedrin promoter control were found to exhibit sixfold higher CAT activity than those infected with recombinant virus expressing the cat gene under the control of the actin promoter. The 24-hr temporal advantage in expression of a passenger gene in infected larvae indicates that the actin-promoter-based expression cassette or other analogous cellular promoter-based cassettes could be used for generating recombinant baculovirus insecticides which could incapacitate pest insects more quickly than viruses employing the polyhedrin or other late viral promoters for expressing insect-incapacitating proteins.

Actins↗
PubMed1996

Nucleotide sequence, temporal expression, and transcriptional mapping of the p34 late gene of the Hz-1 insect virus.

A late gene of the Hz-1 insect virus (Hz-1V) encoding a predicted polypeptide of 34 kilodaltons (kDa) was isolated from a cDNA library and mapped to the HindIII-T region (50.3 to 52.4 map units) of the viral genome. The p34 gene was characterized by DNA sequence, Northern blot, and primer extension analyses. The 765-bp open reading frame (ORF) is transcribed in the clockwise direction as a 1.2-kb RNA. Primer extension analysis detected two late transcription initiation sites at -16 and -17 nt relative to the start of the p34 ORF. Transcription initiation was observed between 4 and 18 hr postinfection (hr p.i.) with maximum expression at 12 hr p.i. No nucleotide sequence homology was detected between the regulatory region of the p34 gene and the baculovirus conserved late promoter motif NTAAG. This observation was substantiated by results obtained from an investigation of Hz-1V late gene expression using a transient expression assay system which suggested that Hz-1V late gene promoters do not resemble the baculovirus late promoter motif. This is the first molecular analysis of Hz-1V late gene expression and offers a basis by which to compare Hz-1V to other insect viruses.

Amino Acid Sequence↗
PubMed1998

Cloning and phylogenetic analysis of chitin synthase genes from the insect pathogenic fungus, Metarhizium anisopliae var. anisopliae.

Degenerated PCR primers were used to amplify chitin synthase genes from genomic DNA of Metarhizium anisopliae var. anisopliae. Through cloning and sequencing of approximately 600-bp fragments amplified by PCR, we found three genes encoding different types of chitin synthases, designated MaCHS1, MaCHS2, and MaCHS3. Southern blot analysis performed on genomic DNA showed that each of the chitin synthases MaCHS1, MaCHS2, and MaCHS3 is encoded by a single copy gene. Alignment of their deduced amino acid sequences with those of other euascomycetes separated the sequences into three distinct classes. MaCHS1 was identified as a gene for class I chitin synthase, MaCHS2 for class II, and MaCHS3 for class III. The UPGMA dendrogram and phylogenetic tree of the deduced amino acid sequences revealed the taxonomic and evolutionary position of Metarhizium anisopliae var. anisopliae.

Amino Acid Sequence↗
PubMed1998

Pantropic retroviral vectors mediate somatic cell transformation and expression of foreign genes in dipteran insects.

The control of insects that transmit disease and damage crops has become increasingly difficult. The ability to genetically engineer insects would facilitate strategies to protect crops and block arthropod vector-borne disease transmission. Transformation vectors based on insect transposable elements have been developed, but most have limited host ranges. A promising alternative is the pantropic retroviral vector, which is packaged with the envelope glycoprotein from vesicular stomatitis virus and is replication-defective. We show here that pantropic murine retroviral vectors can mediate high-level expression of foreign genes in somatically transformed insect larvae and adults of three dipteran genera. This success demonstrates the potential for germline transformation mediated by pantropic retroviral vectors.

Aedes↗
PubMed1988

Baculoviruses for foreign gene expression in insect cells.

Insect baculovirus vector systems are rapid and convenient means of obtaining substantial quantities of many different foreign gene products. The vector systems are proving useful in academic research and in industry. Numerous examples of the successful high-level expression of biologically active vertebrate proteins have been reported. Cleavage of mammalian signal sequences occurred correctly in the cases studied. Vertebrate and invertebrate core glycosylation appears to be similar, but terminal glycosylation differs substantially. Nevertheless, many biologically active glycosylated vertebrate proteins can be expressed in biologically active form using this system. The ease and rapidity of the vector systems are two of their most valuable features. The vectors will be particularly convenient for the rapid analysis of the products of genes subjected to site-specific modifications.

Animals↗
PubMed2006

Social insects: from selfish genes to self organisation and beyond.

Selfish gene and self-organisation approaches have revolutionised the study of social insects and have provided unparalleled insights into the highly sophisticated nature of insect social evolution. Here, we briefly review the core programs and interfaces with communication and recognition studies that characterise these fields today, and offer an interdisciplinary future perspective for the study of social insect evolutionary biology.

Animals↗