Antigen presentation genes in gadoid species (haddock: Melanogrammus aeglefinus and Atlantic cod: Gadus morhua) raise questions about cross-presentation pathways and glycosylated beta-2-microglobulin.

The Atlantic cod immune system deviates from antigen presentation processes seen in other vertebrates in that it lacks the necessary genes for exogenous antigen presentation (i.e., MHC-II and li) and a key MHC-II interacting molecule necessary for T-helper cell function (i.

Characterization of cDNA clones encoding major histocompatibility class II receptors from walleye (Sander vitreus).

The teleost major histocompatibility (MH) class II receptor presents peptides from exogenous sources to CD4 T cells, leading to the initiation of the adaptive immune response. The genes encoding MH class II have been identified in a number of teleost species, but not in walleye, an important recreational fish and commercial fishery in North America. In this study, we cloned and characterized the sequences encoding walleye MH class II α and β chains.

CK-2 of rainbow trout (Oncorhynchus mykiss) has two differentially regulated alleles that encode a functional chemokine.

Rainbow trout chemokine 2 (CK-2) is currently the only known CC chemokine to have a mucin stalk. Further analysis of the mucin stalk region revealed a second, related CC chemokine sequence, denoted here as CK-2.1.

A comparison of rainbow trout cell lines for their expression of the major histocompatibility complex genes and the induction of beta-2-microglobulin by dsRNA.

Western blotting with polyclonal antisera to polypeptides of the rainbow trout major histocompatibility (MH) genes and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to compare expression of MH genes in rainbow trout cell lines. One line was the spleen monocyte/macrophage-like RTS11, which grew loosely on plastic surfaces. Adherent cell lines were fibroblast-like RTG-2 from gonads and four epithelial-like cell lines from gill, intestine, liver and hepatoma: RTgill-W1, RTgutGC, RTL-W1, and RTH-149 respectively.

Characterization of rainbow trout CHK2 and its potential as a genotoxicity biomarker.

Checkpoint kinase 2 (CHK2) plays a central and conserved role in the eukaryotic DNA damage response. Few cell cycle checkpoint proteins have been examined in aquatic organisms, and this study is the first to characterize CHK2 expression in a fish species. CHK2 was cloned from Oncorhynchus mykiss, the rainbow trout.

Cloning and characterization of a cDNA encoding walleye (Sander vitreum) beta-2 microglobulin.

Beta(2)-microglobulin (beta(2)m) is an essential component of the MHC class I antigen presentation pathway, necessary for heavy chain folding and peptide binding. In this study a beta(2)m cDNA isolated from a walleye head kidney library was sequenced and found to be similar to other known beta(2)m sequences. The clone encodes a predicted protein sequence of 116 residues, with a mature peptide 100 amino acids in length.

A cell line (HEW) from embryos of haddock (Melanogrammus aeglefinius) and its capacity to tolerate environmental extremes.

Cell lines can be useful experimental tools for studying marine fish, which are often difficult to routinely obtain and maintain in the laboratory. As few cell lines are available from coldwater marine fish, cultures were initiated from late gastrula embryos of haddock (Melanogrammus aeglefinus) in Leibovitz's L-15 with fetal bovine serum (FBS). From one culture, a cell line (HEW) emerged that has been grown for close to 100 population doublings, was heteroploid, and expressed telomerase activity, all of which suggest HEW is immortal.

Major histocompatibility class II genes in rainbow trout (Oncorhynchus mykiss) exhibit temperature dependent downregulation.

Major histocompatibility (MH) class II receptors are expressed on the surface of specialized antigen-presenting cells in vertebrate immune systems. Their function is to present peptides derived from exogenous pathogens to CD4+ T cells. Variation in the level of expression of these genes has been linked to pathogenesis in various diseases.

Lens and retina formation require expression of Pitx3 in Xenopus pre-lens ectoderm.

Pitx3 is expressed in tissues fated to contribute to eye development, namely, neurula stage ectoderm and pre-chordal mesoderm, then presumptive lens ectoderm, placode, and finally lens. Pitx3 overexpression alters lens, optic cup, optic nerve, and diencephalon development. Many of the induced anomalies are attributable to midline deficits; however, as assessed by molecular markers, ectopic Pitx3 appears to temporarily enlarge the lens field.

Analysis of genomic and expressed major histocompatibility class Ia and class II genes in a hexaploid Lake Tana African 'large' barb individual (Barbus intermedius).

Expression of too many co-dominant major histocompatibility complex (MHC) alleles is thought to be detrimental to proper functioning of the immune system. Polyploidy of the genome will increase the number of expressed MHC genes unless they are prone to a silencing mechanism. In polyploid Xenopus species, the number of MHC class I and II genes has been physically reduced, as it does not increase with higher ploidy genomes.

Molecular cloning and characterization of calreticulin from rainbow trout ( Oncorhynchus mykiss).

Calreticulin (CRT) is a highly conserved, high-capacity, calcium-binding protein shared among vertebrates, invertebrates and higher plants. Its biological importance, highlighted by its highly conserved nature, is supported by its crucial physiological and immunological functions. Within the endoplasmic reticulum, CRT serves as a calcium modulator and a lectin-like chaperone for glycoproteins, especially class I major histocompatibility receptors.

Molecular cloning and characterization of rainbow trout (Oncorhynchus mykiss) C5a anaphylatoxin receptor.

In the course of suppression subtractive hybridization between the cDNA of phytohemagglutinin-stimulated and non-stimulated head kidney cells in rainbow trout (Oncorhynchus mykiss), a cDNA clone was obtained that showed most similarity to mammalian receptor for the anaphylatoxin of the fifth complement component (C5aR). The rainbow trout C5aR cDNA contains a 1,679-bp nucleotide sequence that encodes a 350-amino-acid putative protein with 29.0-31.

Molecular cloning and characterization of rainbow trout (Oncorhynchus mykiss) CCAAT/enhancer binding protein beta.

A full-length cDNA encoding CCAAT/enhancer-binding protein beta (C/EBPbeta) was cloned from rainbow trout by anchored PCR. The putative 291 amino acid protein has 53% and 32% identity to the zebrafish and Japanese flounder sequences, respectively, and 30-34% identity to tetrapod homologues. This clone contains most conserved C/EBPbeta domains except the second transactivation domain just like the zebrafish homologue.

Genomic cloning of novel isotypes of the rainbow trout interleukin-8.

A cDNA clone, designated IL-8nL, was obtained by suppression subtractive hybridisation between lipopolysaccharide-stimulated and non-stimulated populations of the rainbow trout macrophage-like cell line, RTS11. IL-8nL was similar but not identical to a recently published sequence of the gene encoding rainbow trout interleukin-8 (IL-8). Amplification of genomic DNA by the polymerase chain reaction (genomic PCR) using a single outbred trout with common primers in the 5' and 3' untranslated regions gave six distinct genomic sequences, including one ( IL-8A) almost identical to that of the published IL-8 gene and another identical to IL-8nL.

Alternate forms of MHC class II-associated invariant chain are not produced by alternative splicing in rainbow trout (Oncorhynchus mykiss) but are encoded by separate genes.

A major limiting factor in understanding teleost major histocompatibility receptor function is the lack of knowledge about antigen presentation accessory molecules. We report here two cDNA clones encoding teleost versions of invariant chain and one encoding a related protein that may play a protease inhibition role in antigen presentation. The two invariant chain equivalents are similar to each other where they overlap, but differ in the presence or absence of a thyroglobulin domain.

Molecular cloning and characterisation of a carp (Cyprinus carpio) cytokine-like cDNA that shares sequence similarity with IL-6 subfamily cytokines CNTF, OSM and LIF.

In the course of suppression subtractive hybridisation between sodium alginate-induced peritoneal cells (SA-PC) and normal head kidney cDNAs in common carp (Cyprinus carpio), a cytokine-like cDNA clone was found. The clone, named M17, contains a 1600bp nucleotide sequence that encodes a 215 amino acid putative protein that would have a pI of 9.01 and would include a 33 amino acid signal peptide.

Cloning and characterization of cDNA clones encoding CD9 from Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss).

In comparison to mammals, relatively few of the molecules involved in teleost immune responses have been isolated and characterized. A rapid method of isolating molecules important for immune function is subtractive hybridization. One such experiment using infectious hematopoietic necrosis virus-infected Atlantic salmon produced several cDNA clones with similarity to mammalian immune-specific genes, including granzyme M (accession no.

The immune responses of common carp, Cyprinus carpio L., injected with carp interleukin-1beta gene.

The function of the common carp, Cyprinus carpio L., interleukin-1beta (IL-1beta) gene was studied by DNA injection. To investigate the immune responses to IL-1beta, a plasmid construct of cytomegalovirus (CMV)-driven carp IL-1beta was injected into the epaxial muscle of carp.

Diversity of complement factor B/C2 in the common carp (Cyprinus carpio): three isotypes of B/C2-A expressed in different tissues.

Complement factor B and C2 are two critical proteases for complement activation. Some bony fish have been reported to possess duplicated genes for B/C2, but there is no direct evidence regarding possible functional divergence. Here, we report the isolation of the second and third isotypes of carp B/C2-A, a close relative of other bony fish B reported to date, and designated B/C2-A2 and B/C2-A3.

Cloning of a novel rainbow trout (Oncorhynchus mykiss) CC chemokine with a fractalkine-like stalk and a TNF decoy receptor using cDNA fragments containing AU-rich elements.

An activation-specific cDNA library was made from phytohaemagglutinin (PHA)-activated haematopoietic cells of the rainbow trout (Oncorhynchus mykiss) using the technique of suppression subtractive hybridization. Several immune system genes were identified, including an interleukin (IL)1 receptor related protein and two invariant chain-like proteins. Many clones showed no similarity by BLAST search, but had AU-rich elements.