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Results for “multigene typing”

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PubMed1989

Polymorphism for the number of tandemly multiplicated glycerol-3-phosphate dehydrogenase genes in Drosophila melanogaster.

A 26-kilobase-pair region encompassing the sn-glycerol-3-phosphate dehydrogenase (sn-glycerol-3-phosphate:NAD+ 2-oxidoreductase, EC 1.1.1.8) locus in Drosophila melanogaster from two natural populations in Japan was surveyed by restriction mapping. Both tandem duplications and triplications in this region were found in both populations. Detailed analysis of 86 chromosome 2 lines revealed restriction site and allozyme polymorphisms in the transcriptional unit: two restriction sites and the allozymes [fast (F) or slow (S)] were polymorphic among both duplication-bearing chromosomes and those carrying the standard sequence. This finding suggests recurrent recombination and/or gene conversion in this 5-kilobase-pair region. The differences observed for restriction site and allozyme haplotypes among the triplicated sequence both within and between populations, together with the distribution in natural populations, suggest a relatively recent ancestry of the triplication events and an independent origin in respective populations. Such events may represent the process of the formation of multigene families [compare Ohta, T. (1987) Genetics 115, 207-213]. Finally, the evolution of this type of polymorphism is discussed.

Animals↗

PubMed1995

CYP52 (cytochrome P450alk) multigene family in Candida maltosa: identification and characterization of eight members.

Previously, we characterized three genes and presented evidence for an n-alkane-inducible cytochrome P450 (P450alk) multigene family in an n-alkane-assimilating and diploid-type yeast, Candida maltosa. In the present report, we isolated and characterized additional members of this gene family, including a total of thirteen P450alk-related sequences (eight genes and five of their alleles). Two sets, each consisting of two genes, were tandemly arranged in the genome. A gene replacement experiment showed that at least one gene had only a single allele in the genome. The determined nucleotide and the deduced amino acid sequences indicated that all had a characteristic constituent for P450s and exhibited amino acid identities from 94% to 37% to each other. Six genes showed relatively higher similarities to each other than to the other two genes and were thus classified into a subfamily. All the members of this subfamily were assigned to the same single chromosome, showing a good correlation between sequence similarity and chromosomal linkage. Although all the genes except for one were induced by n-alkane, their inducibilities by some other aliphatic carbon sources showed variabilities.

Alleles↗

PubMed1986

Nucleotide sequence, tissue-specific expression, and chromosome location of human carbonic anhydrase III: the human CAIII gene is located on the same chromosome as the closely linked CAI and CAII genes.

The carbonic anhydrases (CA) are a class of metalloenzymes that catalyze the reversible hydration of carbon dioxide. The genes for the carbonic anhydrase isozymes are members of a multigene family that are differentially expressed in a number of cell types. We have isolated a full-length representative of a CAIII mRNA transcript from an adult human muscle cDNA library, and we present the complete nucleotide sequence of this cDNA clone. RNA blots demonstrate that CAIII messages can be detected in a variety of cell types but that high-level expression is limited to human fetal and adult skeletal muscle and to rodent slow skeletal muscle and liver. In addition, we have used a panel of human-mouse cell hybrids to localize the human CAIII gene to chromosome 8. Previous reports have established the CAI and CAII isozyme genes to be closely linked on chromosome 8, and the assignment of the CAIII gene to the same chromosome raises the possibility that these genes may all be linked at a single complex locus.

Animals↗

PubMed1990

Maize regulatory gene opaque-2 encodes a protein with a "leucine-zipper" motif that binds to zein DNA.

The opaque-2 locus (o2) in maize regulates the expression of many members of the zein multigene family of storage proteins. cDNA clones for a wild-type allele of the (o2) locus (O2) were isolated from a maize endosperm cDNA library and sequenced. We found a 258-nucleotide 5' leader sequence containing three short open reading frames followed by a sequence specifying a protein of 437 amino acids. The presumptive amino acid sequence of the protein (O2) specified by the O2 cDNA contains a "leucine-zipper" domain characteristic of some mammalian and fungal transcription activation factors. lacZ-O2 fusion constructs, using nearly the entire coding region of O2 or only a fragment specifying the leucine-zipper domain, were expressed in Escherichia coli. In an in vitro binding assay, the beta-galactosidase-O2 fusion proteins bound to two specific regions on the 5' side of the coding sequence in a zein genomic clone. This suggests that the O2 protein affects zein transcription through direct interaction with one or more zein promoter elements.

Amino Acid Sequence↗

PubMed1992

Organization of the human skeletal myosin heavy chain gene cluster.

Myosin is an important structural and enzymatic component of skeletal muscle. Multiple myosin isoforms are encoded by a multigene family and are expressed in different developmental stages and fiber types. In humans and mice, skeletal myosin heavy chain (MYH) genes are clustered on a single chromosome (17p and 11, respectively). Since the structural organization of the gene cluster may affect its expression as well as shed light on MYH genetic alterations, a physical map of the human MYH gene cluster was constructed. Nine yeast artificial chromosomes containing MYH genes were isolated and used to construct a contiguous set (contig) of overlapping yeast artificial chromosomes. This contig encompasses a genetic marker mapped to 17p13.1. Six MYH genes were located within a 500-kilobase segment of human DNA. The order of the genes within this cluster does not correspond to the developmental pattern of expression of individual members.

Base Sequence↗

PubMed1999

Molecular biology of the interactions between connexins.

The protein structural component of gap junctions is the connexin. Studies on the association properties of the connexins to form heteromeric connexons and heterotypic gap junctions are necessary for a complete understanding of the role of different connexins in gap junction function. The connexins are coded by a multigene family consisting of at least 16 members. Most cells express multiple types of connexin that can potentially associate to form gap junction channels containing more than one type of connexin. The permeability and gating characteristics of gap junction channels are dependent on the isoform and post-translational modifications present on the connexins and their association properties. Together with an observed selectivity in the association properties of the different connexins and the development of more specific perturbation approaches, these studies have provided insights into the significance of connexin diversity and the temporal expression patterns for connexins that have been determined in vivo in both developmental and differentiating systems.

Amino Acid Sequence↗

PubMed2002

A distinct 5' flanking var gene region regulates Plasmodium falciparum variant erythrocyte surface antigen expression in placental malaria.

The Plasmodium falciparum multigene var family codes for approximately 50 variant adhesive proteins expressed in a mutually exclusive manner at the surface of infected red blood cells (iRBCs). Switching expression of var genes can lead to fundamental changes in the adhesive and antigenic properties of iRBCs. For example, a specific phenotypic switch in adhesion from CD36 to chondroitin sulphate A (CSA) is associated with malaria pathogenesis in pregnant women. The factors and DNA elements that control the expression of a particular member of the var gene family during gestational malaria remains enigmatic. Here, we report that the subtelomeric FCR3 varCSA is expressed under the control of a unique DNA element of 1.8 kb, whereas the other members of the var multigene family are flanked by common regulatory elements. The 5' varCSA-type element is conserved as a single copy in laboratory strains and clinical isolates from Brazil and West Africa and contains two distinct repetitive elements of 150 bp and 60 bp respectively. The 5' varCSA-type sequence tags a var gene in the 3D7 genome that is homologous to the FCR3 varCSA gene. A recombinant DBL gamma domain of this var gene showed specific binding to CSA. This subtelomeric varCSA gene is transcribed in the opposite sense when compared with the usual orientation of telomere-adjacent var genes. This unique arrangement might explain why the varCSA gene is relatively conserved in genetically distinct parasites despite being located in a highly recombinogenic chromosome compartment. The 5' untranslated region (UTR) of the varCSA-type sequence is also transcribed in placental isolates that bind to CSA, illustrating an important role for the unique 5' varCSA-type sequence in the regulation of var genes involved in malaria pathogenesis in pregnant women. However, this promoter is not always found to be transcribing var genes selected for expression of products that bind to CSA in vitro. Our work identifies a sequence tag for the identification of varCSA genes in placental isolates for the first time.

5' Untranslated Regions↗

PubMed2004

Muscular myosin isoforms of Taenia solium (Cestoda).

Type II myosin, the primary component of the thick filament of muscle fibers, is organized as a dimeric high molecular weight protein, and is composed of a pair of heavy chains (MHC) and two pairs of light chains. Myosin II transforms ATP energy into mechanical force. All type II myosins are conserved proteins but they have two variable regions that are located in different places of the molecule. Myosin molecules are encoded by a multigene family and many isoforms are generated. The expression of myosins depends on the developmental stage and on the type and degree of contractile activity and tissue, therefore several myosin isoforms are found in the same organism. Here we describe the use of different techniques that allowed demonstrating the presence of isoforms of the heavy chain type II myosin of Taenia solium cysticerci (larvae) and tapeworms (adults), a cestode parasite of importance in public health in many developing countries. Myosin was purified and used in comparative proteolytic fragmentation, ATPase activity, detection of antigenic differences and electrophoretic separation. The results obtained showed biochemical and immunochemical differences among cysticerci and tapeworms, and demonstrate the presence of myosin isoforms in T. solium that are probably associated to physiological requirements of each developmental stage.

Adenosine Triphosphatases↗

PubMed1994

Cloning, analysis, and chromosomal localization of myoxin (MYH12), the human homologue to the mouse dilute gene.

The mouse dilute gene encodes a novel type of non-muscle myosin that structurally combines elements from both nonmuscle myosin type I and nonmuscle myosin type II. Phenotypically, mutations in the mouse dilute gene result not only in the lightening of coat color, but also in the onset of severe neurological defects shortly after birth. This may indicate that the mouse dilute gene is important in maintaining the normal neuronal function in the mouse. We report the isolation and sequencing of "myoxin" (MYH12), the human homologue of the mouse dilute gene, and its assignment to human chromosome 15.

Amino Acid Sequence↗

PubMed1999

Gibberellin-responsive genes: high level of transcript accumulation in leaf sheath meristematic tissue from Zea mays L.

In order to identify genes that are related to the gibberellin (GA) response in maize (Zea mays L.), mRNA species from wild-type and single-gene dwarf mutants, d5 and D8, were compared by fluorescent differential display. The d5 mutant is unable to produce biologically active GA, but recovers its tall stature on exogenous application of GA. D8 is insensitive to GA, despite the accumulation of a high level of endogenous GA, suggesting it to be a receptor mutant or a mutant in signal transduction pathway(s). After screening 7000 cDNA populations, one clone was isolated, for which transcripts were rare in d5 shoots but accumulated within 1 h after GA3 application. This clone, designated as ZmGR1a, encodes a polypeptide with a relative molecular mass of ca. 13 kDa, which shows significant homology to proline-rich proteins from several plant species. A similar experiment with D8 identified a clone, ZmGR2a, with low transcript levels, but accumulation within 6 h after GA3 treatment of d5 shoots. ZmGR2a encodes a polypeptide with a relative molecular mass of ca. 19 kDa, which shows no significant homology with any known protein. Southern blot analysis indicated that ZmGR1a and ZmGR2a form a small multigene family within the maize genome. In situ hybridization with wild-type seedlings showed transcripts on both to be abundant in leaf sheath meristematic tissue, in which GA enhances cell elongation and cell division.

Amino Acid Sequence↗

PubMed1999

Expanding our understanding of immunoglobulin, T-cell antigen receptor, and novel immune-type receptor genes: a subset of the immunoglobulin gene superfamily.

The immunoglobulin superfamily (IgSF) is an extensively diversified multigene family whose members share a common structural feature, the Ig fold. Members of the Ig/T-cell antigen receptor (TCR) subset of the IgSF mediate antigen-specific recognition in adaptive immune responses. Antigen-binding receptors belonging to this subset are present in all species of jawed vertebrates. To explore whether there are additional structurally related but otherwise distinct members of this subset, we have developed a technique termed the short-primer polymerase chain reaction (PCR) that targets structurally conserved short motifs in the Ig fold. Large-scale sequencing efforts and recent advances in information biotechnology, including "electronic PCR," provide additional computational means to implement similarly directed searches within databases. The use of these approaches has led to the discoveries of Ig/TCR homologues in a variety of phylogenetically diverse organisms, a diversified family of novel immune-type receptor genes, as well as a novel human IgSF member. The potential of random sequencing efforts and virtual screening of databases is described in the context of two novel genes in bony fish. The various methodologies that are discussed and the examples shown provide means for further investigating, and/or elucidating novel, IgSF receptors as well as components of pathways that are involved in immune responses in both traditional and nontraditional model systems.

Amino Acid Sequence↗

PubMed2025

Identification of OxyR as an activator of type 1 fimbriae (fim) in Salmonella enterica serovar Typhi.

Salmonella enterica serovar Typhi (S. Typhi) encodes 14 fimbrial gene clusters, including the mannose-binding type 1 fimbriae known as Fim. Type 1 fimbriae have been implicated in biofilm formation and adhesion to host cells in Salmonella. However, their regulation in S. Typhi remains largely unknown. To identify genes affecting the regulation of fim in S. Typhi, we employed both a targeted and a genome-wide transposon-based screening approach. Overall, we identified 18 potential regulators of fim expression: 10 activators and 8 repressors. Two genes involved in the electron transport chain, yqiC and ndh, which encode the type II NADH dehydrogenase NDH-2, were identified. Both YqiC and NDH-2 contribute to the production of reactive oxygen species, prompting an investigation into the roles of oxidative stress response regulators OxyR and SoxR. We found that only OxyR regulates fim expression, which was specific to S. Typhi. OxyR acts by directly binding to the fimA promoter region. This study paves the way for future development of anti-adhesion strategies through the identification of 14 novel regulators for the most prominent fimbriae of S. Typhi.IMPORTANCEAdhesion mediated by fimbriae is one of the critical steps in the infection process. Therefore, it is essential to better understand the regulation of type 1 fimbriae (fim) in the human-specific pathogen Salmonella enterica serovar Typhi, the etiologic agent of typhoid fever. In this study, we identified 18 distinct mutants with altered regulation of fim. Furthermore, we confirmed that the DNA-binding protein OxyR directly regulates fim expression. Importantly, we also demonstrated regulatory differences in fim expression between S. Typhi and S. Typhimurium, as six of the genes identified altering fim expression in S. Typhi either did not affect fim expression in S. Typhimurium or had the contrary effect. This highlights fundamental differences between these serovars and emphasizes the need to investigate and compare aspects of gene regulation in S. Typhi.

Salmonella typhi↗

PubMed1993

Embryonic and fetal rat myoblasts express different phenotypes following differentiation in vitro.

Myosin heavy chain (MHC) is encoded by a multigene family containing members which are expressed in developmental and fiber type-specific patterns. In developing rats, primary (1 degree) and secondary (2 degrees) myotubes can be distinguished by difference in MHC expression: 1 degree myotubes coexpress embryonic and slow MHC, while 2 degrees myotubes initially express only embryonic MHC. We have used monoclonal antibodies which recognize the embryonic, slow, neonatal, and adult fast IIB/IIX MHCs to examine MHC accumulation in myoblasts obtained from hindlimbs of embryonic day (ED) 14 and ED 20 Sprague-Dawley rats during differentiation in vitro. Embryonic myoblasts (ED 14), which develop into 1 degree myotubes in vivo, differentiate as myocytes or small myotubes (i.e., 1-4 nuclei) which express both embryonic and slow MHC. They do not accumulate detectable levels of neonatal or adult fast IIB/IIX MHC. Fetal myoblasts, which develop into secondary myotubes in vivo, fuse to form large myotubes (i.e., 10-50 nuclei) and express predominantly embryonic MHC at 3 days in culture. These myotubes accumulate neonatal and adult fast IIB/IIX isoforms of MHC and eventually contract spontaneously. In contrast to embryonic myotubes, they do not accumulate slow MHC. Our results demonstrate that embryonic and fetal rat myoblasts express different phenotypes in vitro and suggest that they represent distinct myoblast lineages similar to those previously described in chickens and mice. These two lineages may be responsible for the generation of distinct populations of 1 degree and 2 degrees myotubes in vivo.

Animals↗

PubMed1993

Structure, function, and regulation of adrenergic receptors.

Adrenergic receptors for adrenaline and noradrenaline belong to the large multigenic family of receptors coupled to GTP-binding proteins. Three pharmacologic types have been identified: alpha 1-, alpha 2-, and beta-adrenergic receptors. Each of these has three subtypes, characterized by both structural and functional differences. The alpha 2 and beta receptors are coupled negatively and positively, respectively, to adenylyl cyclase via Gi or Gs regulatory proteins, and the alpha 1 receptors modulate phospholipase C via the Go protein. Subtype expression is regulated at the level of the gene, the mRNA, and the protein through various transcriptional and postsynthetic mechanisms. Adrenergic receptors constitute, after rhodopsin, one of the best studied models for the other receptors coupled to G proteins that are likely to display similar structural and functional properties.

Amino Acid Sequence↗

PubMed1998

Sequence analysis of a 62-kb region overlapping the human KLRC cluster of genes.

The NKG2 family of genes (HGMW-approved symbol KLRC) contains at least four members (NKG2-A, -C, -E, and -F) which are localized to human chromosome 12p12.3-p13.2. This region, called the natural killer (NK) complex, encodes for lectin-like genes preferentially expressed on NK cells. One of them, the human CD94 gene (HGMW-approved symbol KLRD1), encodes for a protein that has been shown to be covalently associated with the NKG2-A molecule. In this report, we showed that the NKG2 and CD94 genes are localized in a small region (< 350 kb) and we mapped them in the following order: (NKG2-C/NKG2-A)/NKG2-E/NKG2-F/NKG2-D/CD 94. Sequence analysis of 62 kb spanning the NKG2-A, -E, -F, and -D loci allowed the identification of two LINE elements that could have been involved in the duplication of the NKG2 genes. Presence of one MIR and one L1ME2 element at homologous positions in the NKG2-A and NKG2-F genes is consistent with the existence of rodent NKG2 gene(s). Finally, we mapped the 5'-ends of the NKG2-A transcripts into two separate regions showing the existence of two separate transcriptional control regions upstream of the NKG2-A locus and defining putative promoter elements for these genes.

Antigens, CD↗

PubMed2000

A sequence-ready physical map of the region containing the human natural killer gene complex on chromosome 12p12.3-p13.2.

We developed a sequence-ready physical map of a part of human chromosome 12p12.3-p13.2 where the natural killer gene complex (NKC) is located. The NKC includes a cluster of genes with structure similar to that of the Ca(2+)-dependent lectin superfamily of glycoproteins that are expressed on the surface of most natural killer (NK) cells and a subset of T cells. These killer cell lectin-like receptors (KLR) are involved in NK target cell recognition, leading to activation or inhibition of NK cell function. We used a number of sequence-tagged site (STS) markers from this region to screen two large insert bacterial artificial chromosome (BAC) libraries and a bacteriophage P1-derived (PAC) chromosome library. The clones were assembled into contiguous sets by STS content analysis. The 72-BAC and 11-PAC contig covers nearly 2 Mb of DNA and provides an average marker resolution of 26 kb. We have precisely localized 17 genes, 5 expressed sequence tags, and 49 STSs within this contig. Of this total number of STS, 30 are newly developed by clone-end sequencing. We established the order of the genes as tel-M6PR-MAFAL (HGMW-approved symbol KLRG1)-A2M-PZP-A2MP-NKRP1A (HGMW-approved symbol KLRB1)-CD69-AICL (HGMW-approved symbol CLECSF2)-KLRF1-OLR1-CD94 (HGMW-approved symbol KLRD1)-NKG2D (HGMW-approved symbol D12S2489E)-PGFL-NKG2F (HGMW-approved symbol KLRC4)-NKG2E (HGMW-approved symbol KLRC3)-NKG2A (HGMW-approved symbol KLRC1)-LY49L (HGMW-approved symbol KLRA1)-cen. This map would facilitate the cloning of new KLR genes and the complete sequencing of this region.

Antigens, CD↗

PubMedDate not supplied

Cloning of human DECTIN-1, a novel C-type lectin-like receptor gene expressed on dendritic cells.

We identified a new Ca2+-dependent lectin-like receptor gene, DECTIN-1 (HGMW-approved symbol CLECSF12), the human orthologue of mouse Dectin-1, coding for a putative type II transmembrane glycoprotein with an extracellular C-type lectin-like domain. The gene structure and two alternative spliced forms of DECTIN-1 are described. The DECTIN-1 gene was localized in the natural killer gene complex on human Chromosome 12p12.3-p13.2, between OLR1 and CD94 (position 21.8 cM on the genetic map). The DECTIN-1 gene is highly expressed at the mRNA level in dendritic cells and is not further up-regulated during the maturation of these cells with tumor necrosis factor-alpha. The DECTIN-1 gene therefore represents a novel human member of the C-type lectin-like receptor gene family preferentially expressed in dendritic cells.

Alternative Splicing↗

PubMed1989

Different gamma-glutamyl transpeptidase mRNAs are expressed in human liver and kidney.

In human, the two subunits of gamma-glutamyl transpeptidase (GGT) arise from a common precursor encoded by a multigene family. Until now, a single specific coding sequence for this precursor (type I) has been identified in human placenta and liver. In the present study, we have isolated from a human kidney cDNA library, a GGT specific clone (0.8 Kb). The sequence of which (type II) i) covers the carboxy terminal part of the GGT precursor, ii) exhibits 22 point mutations and a 30 bp deletion as compared to the type I GGT sequence. The sequencing of a human genomic clone reveals that this type II GGT mRNA is encoded by a different gene than the type I GGT mRNA. Both type I and type II GGT mRNAs are expressed in human liver, while almost exclusively type II GGT mRNA is detected in human kidney.

Adult↗