Dataset Information

B cell receptor accessory molecule CD79?: characterisation and expression analysis in a cartilaginous fish, the spiny dogfish (Squalus acanthias).

ABSTRACT: CD79? (also known as Ig?) is a component of the B cell antigen receptor complex and plays an important role in B cell signalling. The CD79? protein is present on the surface of B cells throughout their life cycle, and is absent on all other healthy cells, making it a highly reliable marker for B cells in mammals. In this study the spiny dogfish (Squalus acanthias) CD79? (SaCD79?) is described and its expression studied under constitutive and stimulated conditions. The spiny dogfish CD79? cDNA contains an open reading frame of 618 bp, encoding a protein of 205 amino acids. Comparison of the SaCD79? gene with that of other species shows that the gross structure (number of exons, exon/intron boundaries, etc.) is highly conserved across phylogeny. Additionally, analysis of the 5' flanking region shows SaCD79? lacks a TATA box and possesses binding sites for multiple transcription factors implicated in its B cell-specific gene transcription in other species. Spiny dogfish CD79? is most highly expressed in immune tissues, such as spleen, epigonal and Leydig organ, and its transcript level significantly correlates with those of spiny dogfish immunoglobulin heavy chains. Additionally, CD79? transcription is up-regulated, to a small but significant degree, in peripheral blood cells following stimulation with pokeweed mitogen. These results strongly indicate that, as in mammals, spiny dogfish CD79? is expressed by shark B cells where it associates with surface-bound immunoglobulin to form a fully functional BCR, and thus may serve as a pan-B cell marker in future shark immunological studies.

SUBMITTER: Li R

PROVIDER: S-EPMC4034164 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature

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Publications

B cell receptor accessory molecule CD79α: characterisation and expression analysis in a cartilaginous fish, the spiny dogfish (Squalus acanthias).

Li Ronggai R Wang Tiehui T Bird Steve S Zou Jun J Dooley Helen H Secombes Christopher J CJ

Fish & shellfish immunology 20130228 6

CD79α (also known as Igα) is a component of the B cell antigen receptor complex and plays an important role in B cell signalling. The CD79α protein is present on the surface of B cells throughout their life cycle, and is absent on all other healthy cells, making it a highly reliable marker for B cells in mammals. In this study the spiny dogfish (Squalus acanthias) CD79α (SaCD79α) is described and its expression studied under constitutive and stimulated conditions. The spiny dogfish CD79α cDNA co ...[more]

PMID: 23454429

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Project description:The spiny dogfish shark (Squalus acanthias) is one of the most commonly used cartilaginous fishes in biological research, especially in the fields of nitrogen metabolism, ion transporters and osmoregulation. Nonetheless, transcriptomic data for this organism is scarce. In the present study, a multi-tissue RNA-seq experiment and de novo transcriptome assembly was performed in four different spiny dogfish tissues (brain, liver, kidney and ovary), providing an annotated sequence resource. The characterization of the transcriptome greatly increases the scarce sequence information for shark species. Reads were assembled with the Trinity de novo assembler both within each tissue and across all tissues combined resulting in 362,690 transcripts in the combined assembly which represent 289,515 Trinity genes. BUSCO analysis determined a level of 87% completeness for the combined transcriptome. In total, 123,110 proteins were predicted of which 78,679 and 83,164 had significant hits against the SwissProt and Uniref90 protein databases, respectively. Additionally, 61,215 proteins aligned to known protein domains, 7,208 carried a signal peptide and 15,971 possessed at least one transmembrane region. Based on the annotation, 81,582 transcripts were assigned to gene ontology terms and 42,078 belong to known clusters of orthologous groups (eggNOG). To demonstrate the value of our molecular resource, we show that the improved transcriptome data enhances the current possibilities of osmoregulation research in spiny dogfish by utilizing the novel gene and protein annotations to investigate a set of genes involved in urea synthesis and urea, ammonia and water transport, all of them crucial in osmoregulation. We describe the presence of different gene copies and isoforms of key enzymes involved in this process, including arginases and transporters of urea and ammonia, for which sequence information is currently absent in the databases for this model species. The transcriptome assemblies and the derived annotations generated in this study will support the ongoing research for this particular animal model and provides a new molecular tool to assist biological research in cartilaginous fishes.

Project description:The first two steps of urea synthesis in liver of marine elasmobranchs involve formation of glutamine from ammonia and of carbamoyl phosphate from glutamine, catalysed by glutamine synthetase and carbamoyl-phosphate synthetase, respectively [Anderson & Casey (1984) J. Biol. Chem. 259, 456-462]; both of these enzymes are localized exclusively in the mitochondrial matrix. The objective of this study was to establish the enzymology of carbamoyl phosphate formation and utilization for pyrimidine nucleotide biosynthesis in Squalus acanthias (spiny dogfish), a representative elasmobranch. Aspartate carbamoyltransferase could not be detected in liver of dogfish. Spleen extracts, however, had glutamine-dependent carbamoyl-phosphate synthetase, aspartate carbamoyltransferase, dihydro-orotase, and glutamine synthetase activities, all localized in the cytosol; dihydro-orotate dehydrogenase, orotate phosphoribosyltransferase, and orotidine-5'-decarboxylase activities were also present. Except for glutamine synthetase, the levels of all activities were very low. The carbamoyl-phosphate synthetase activity is inhibited by UTP and is activated by 5-phosphoribosyl 1-pyrophosphate. The first three enzyme activities of the pyrimidine pathway were eluted in distinctly different positions during gel filtration chromatography under a number of different conditions; although complete proteolysis of inter-domain regions of a multifunctional complex during extraction cannot be excluded, the evidence suggests that in dogfish, in contrast to mammalian species, these three enzymes of the pyrimidine pathway exist as individual polypeptide chains. These results: (1) establish that dogfish express two different glutamine-dependent carbamoyl-phosphate synthetase activities, (2) confirm the report [Smith, Ritter & Campbell (1987) J. Biol. Chem. 262, 198-202] that dogfish express two different glutamine synthetases, and (3) provide indirect evidence that glutamine may not be available in liver for biosynthetic reactions other than urea formation.

Dataset Information

B cell receptor accessory molecule CD79?: characterisation and expression analysis in a cartilaginous fish, the spiny dogfish (Squalus acanthias).

Publications

B cell receptor accessory molecule CD79α: characterisation and expression analysis in a cartilaginous fish, the spiny dogfish (Squalus acanthias).

Similar Datasets

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