Control of vitellogenin genes expression by sequences derived from transposable elements in rainbow trout.

In most of oviparous animals, vitellogenins (VTG) are the major egg yolk precursors. They are produced in the liver under the control of estrogens. In rainbow trout (Oncorhynchus mykiss), the vtg genes cluster contains an unusually large number of almost identical gene copies.

The identification and characterisation of a functional interaction between arginyl-tRNA-protein transferase and topoisomerase II.

Topoisomerase II is required for the viability of all eukaryotic cells. It plays important roles in DNA replication, recombination, chromosome segregation, and the maintenance of the nuclear scaffold. Proteins that interact with and regulate this essential enzyme are of great interest.

The identification of a functional interaction between PKC and topoisomerase II.

Topoisomerase II plays an essential role in the segregation of chromosomes during cell division. It is also a major component of the nuclear matrix. Proteins that interact with and regulate this essential enzyme are of great interest.

Non-PCR methods for the analysis of CFTR transcripts.

Cystic fibrosis transmembrane conductance regulator gene (CFTR) shows a complex mechanism of tissue-specific and temporal regulation. CFTR mRNA detection and measurement are extremely difficult because of the low to very low levels of its endogenous expression. In this paper, we describe four different non-PCR methods optimized to analyze CFTR transcripts in epithelial cell lines, primary cell lines and native tissues that express significant amounts of CFTR transcript.

Quantitative methods for the analysis of CFTR transcripts/splicing variants.

In cystic fibrosis (CF), transcript analysis and quantification are important for diagnosis, prognosis and also as surrogate markers for some therapies including gene therapy. Classical RNA-based methods require significant expression levels in target samples for appropriate analysis, thus PCR-based methods are evolving towards reliable quantification. Various protocols for the quantitative analysis of CFTR transcripts (including those resulting from splicing variants) are described and discussed here.

Analysis of genomic CFTR DNA.

There are numerous methodologies available for the analysis of genomic CFTR DNA. We present here the basic tools to allow a thorough investigation of the CFTR gene, beginning with the identification of potential regulatory regions using DNase I hypersensitive sites, and continuing with methods for the detection of mutations: denaturing High Performance Liquid Chromatography (dHPLC), Single Strand Conformation Polymorphism (SSCP), and allele-specific oligonucleotide (ASO) hybridisation. Also provided is a comprehensive set of PCR primers for the amplification of most regions of the CFTR gene.

Alternative splicing of the ovine CFTR gene.

Alternative splicing of the human CFTR gene was studied previously and shown not to generate functional CFTR-like chloride ion channels. However, it is possible that some of the alternatively spliced forms may encode CFTR proteins with different functions. The ovine CFTR gene is very similar to the human gene and has regulatory mechanisms in common.

HNF1alpha is involved in tissue-specific regulation of CFTR gene expression.

The CFTR (cystic fibrosis transmembrane conductance regulator) gene shows a complex pattern of expression with tissue-specific and temporal regulation. However, the genetic elements and transcription factors that control CFTR expression are largely unidentified. The CFTR promoter does not confer tissue specificity on gene expression, suggesting that there are regulatory elements outside the upstream region.

Experimentally revised repertoire of putative contingency loci in Neisseria meningitidis strain MC58: evidence for a novel mechanism of phase variation.

Analysis of the genome sequence of Neisseria meningitidis strain MC58 revealed 65 genes associated with simple sequence repeats. Experimental evidence of phase variation exists for only 14 of these 65 putatively phase variable genes. We investigated the phase variable potential of the remaining 51 genes.

A comparative genomic analysis of the cow, pig, and human CFTR genes identifies potential intronic regulatory elements.

The identification of sequences within noncoding regions of genes that are conserved between several species may indicate potential regulatory elements. This is important for genes with complex control mechanisms such as the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR demonstrates similar patterns of temporal and spatial expression in human and sheep, but these differ significantly in mouse cftr.

Alternative 5' exons of the CFTR gene show developmental regulation.

The cystic fibrosis transmembrane conductance regulator (CFTR) gene shows a complex mechanism of tissue-specific and temporal regulation. Expression of the sheep and human CFTR genes shows a gradual decline during lung development, from the early mid-trimester through to term. Alternative upstream exons of CFTR have been identified in several species but their functional role remains obscure.

Temporal regulation of CFTR expression during ovine lung development: implications for CF gene therapy.

The cystic fibrosis transmembrane conductance regulator (CFTR) protein is a small conductance chloride ion channel that may interact directly with other channels including the epithelial sodium channel (ENaC). CFTR is known to be more abundant in the airway epithelium during the second trimester of human development than after birth. This could be a consequence of the change in function of the respiratory epithelium from chloride secretion to sodium absorption near term.

The sheep genome contributes to localization of control elements in a human gene with complex regulatory mechanisms.

Genes that show complex tissue-specific and temporal control by regulatory elements located outside their promoters present a considerable challenge to identify the sequences involved. The rapid accumulation of genomic sequence information for a number of species has enabled a comparative phylogenetic approach to find important regulatory elements. For some genes, which show a similar pattern of expression in humans and rodents, genomic sequence information for these two species may be sufficient.

Genomic analysis of the vitellogenin locus in rainbow trout (Oncorhynchus mykiss) reveals a complex history of gene amplification and retroposon activity.

Vitellogenins (Vtg) are the major yolk proteins in most oviparous organisms. They are encoded by a small number of genes--between one and four depending on the species. Characterization of the Vtg region in the genome of the rainbow trout reveals unusual features, however, in that this locus contains twenty complete genes and ten pseudogenes per haploid genome.

Structure of a fish (Oncorhynchus mykiss) vitellogenin gene and its evolutionary implication.

In this paper we describe the first complete structure of a fish vitellogenin gene. A 22 kb genomic region from rainbow trout (Oncorhynchus mykiss) was cloned and analysed. This region was shown to contain two tandemly arranged vitellogenin genes.

Characterization of vitellogenin from rainbow trout (Oncorhynchus mykiss).

The nucleotide sequence of the vitellogenin cDNA from the rainbow trout Oncorhynchus mykiss was determined. Analysis of the deduced amino acid sequence (1659 residues) places the lipovitellin I, phosvitin and lipovitellin II domains between amino acids 16 to 1088, 1089 to 1145 and 1146 to 1659, respectively. The general structure is similar to other vertebrate vitellogenins except for the serine rich phosvitin domain which is the shortest identified so far in vertebrates (57 amino acids), being 2 to 4 times smaller than in other species.

Cloning of a teleost fish glucocorticoid receptor shows that it contains a deoxyribonucleic acid-binding domain different from that of mammals.

In the teleost fish, physiological and biochemical studies suggest that glucocorticoids regulate both salt balance and metabolic activities. In mammals, however, these functions are divided between glucocorticoids and mineralocorticoids. In mammals, separate receptors for these two classes of steroid hormone have been cloned and sequenced.