Rabbit oviductal glycoprotein 1 gene: genomic organization polymorphism analysis and mRNA expression

The OVGP1 is an oviductal glycoprotein that has positive effects on fertilization and early embryo development. We have amplified and sequenced the rabbit OVGP1 gene, which spans 13 kb and it is formed by 11 exons and 10 introns. To find polymorphisms, a region encompassing the promoter to intron 1 has been sequenced in 22 rabbits of the H, V, R, and A Spanish lines. We have identified five SNPs and one triallelic microsatellite in the promoter region, and three SNPs and one dinucleotide INDEL in intron 1. The 10 polymorphic sites cosegregate forming two haplotypes. The allelic frequencies of the microsatellite have been analyzed in 98 rabbits belonging to the four lines and the three alleles were found in all the lines. The relative quantification of the OVGP1 mRNA in liver, kidneys, lungs, skeletal muscle, ovary, uterus, and oviduct reveals that the OVGP1 expression in the oviduct is 5,500 higher than in the uterus or ovary, whereas a low level of basal expression is detected in non-reproductive tissues. We have also compared the mRNA expression between samples of oviducts taken from non-mated rabbit and samples of oviducts at different stages of the early pregnancy, but no significant differences were found.     

Odorant receptor gene regulation: implications from genomic organization.

Odorant receptor genes comprise the largest known family of G-protein-coupled receptors in vertebrates. These receptor genes are tightly clustered in the genomes of every vertebrate organism investigated, including zebrafish, mice and humans, and they appear to have expanded and duplicated throughout evolution. In a mechanism that has yet to be elucidated, each olfactory neuron expresses a single receptor gene. This highly restricted expression pattern underlies the ability to distinguish between a wide variety of odorants. Here, we address the evolutionary expansion of odorant receptor genes and the role genomic organization of these genes might have in their tightly regulated expression.     

Revised genomic organization of FBN1 and significance for regulated gene expression

FBN1 encodes fibrillin-1, an extracellular matrix protein that is defective in Marfan syndrome. This gene is divided into 65 exons and was previously reported to be approximately 110 kb in length. The existence of 3 exons upstream of the exon containing the putative initiating methionine left open the possibility of alternative fibrillin-1 isoforms that vary at their N-termini. Detailed examination of YACs containing human FBN1 reveal that the gene is 200 kb, almost twice as large as previously thought. Characterization of the porcine FBN1 cDNA and 5' flanking sequence demonstrates extreme conservation between the pig and the human predicted proteins and argues against the possibility of alternative amino-terminal coding sequence. These data further our understanding of the regulatory requirements for gene expression and establish a framework for recombinant expression of fibrillin-1.     

CD28-Mediated regulation of mRNA stability requires sequences within the coding region of the IL-2 mRNA.

Using sequence-tagged genomic reporter constructs, we investigated the contribution of IL-2 sequences to CD28-mediated regulation of mRNA stability. We find that CD28 signaling acts transiently to stabilize the IL-2 mRNA following T cell activation. Such stabilization requires sequences within both exon 2 and the coding region of exon 4. Unexpectedly, CD28 signaling at later times enhances the decay of the IL-2 mRNA. This CD28-dependent decay of IL-2 mRNA requires sequences localized between exon 3 and the stop codon. Our findings demonstrate that the coding region of the IL-2 mRNA contains previously undefined CD28-responsive sequence elements that are critical for the regulation of mRNA stability.     

Coordinate gene regulation during hematopoiesis is related to genomic organization

Gene loci are found in nuclear subcompartments that are related to their expression status. For instance, silent genes are often localized to heterochromatin and the nuclear periphery, whereas active genes tend to be found in the nuclear center. Evidence also suggests that chromosomes may be specifically positioned within the nucleus; however, the nature of this organization and how it is achieved are not yet fully understood. To examine whether gene regulation is related to a discernible pattern of genomic organization, we analyzed the linear arrangement of co-regulated genes along chromosomes and determined the organization of chromosomes during the differentiation of a hematopoietic progenitor to erythroid and neutrophil cell types. Our analysis reveals that there is a significant tendency for co-regulated genes to be proximal, which is related to the association of homologous chromosomes and the spatial juxtaposition of lineage-specific gene domains. We suggest that proximity in the form of chromosomal gene distribution and homolog association may be the basis for organizing the genome for coordinate gene regulation during cellular differentiation.     

The cloning,genomic organization and tissue expression profile of the human DLG5 gene

Background  

Familial atrial fibrillation, an autosomal dominant disease, was previously mapped to chromosome 10q22. One of the genes mapped to the 10q22 region is DLG5, a member of the MAGUKs (Membrane Associated Gyanylate Kinase) family which mediates intracellular signaling. Only a partial cDNA was available for DLG5. To exclude potential disease inducing mutations, it was necessary to obtain a complete cDNA and genomic sequence of the gene.     

The genomic organization,promoter position and expression profile of the mouse MRG15 gene

MORF4 (mortality factor on chromosome 4) and the novel related MRG (MORF4-related gene) gene family were identified when MORF4 was shown to induce senescence in a subset of tumor cell lines. The gene on chromosome 15 (MRG15) has high similarity to Drosophila MSL3, which is a component of the dosage compensation complex. MRG15 also has a chromodomain and may therefore function as a chromatin remodeling factor in a complex(es) involving a histone acetyltransferase, similar to MSL3. To complement our studies on human MRG15, we cloned and characterized the mouse MRG15 gene. Mouse MRG15 is expressed ubiquitously in adult tissues and at various embryonic stages, and expression in adult testis is higher than in other tissues. MRG15-b, which is an alternatively spliced form of MRG15-a and has a 39-amino-acid insertion in the chromodomain, is also expressed in all mouse tissues examined and localizes to the nucleus of cells. It is possible that MRG15-b may lack the function of the chromodomain because of the additional amino acids and could potentially be the equivalent of the human MORF4 in the mouse. The mouse MRG15 gene is composed of twelve exons and spans over 24 kb DNA. Using luciferase constructs we have determined that there is a functional promoter sequence 1.8 kb upstream of the ATG start codon. This region contains no TATA box but has GC-rich regions, consistent with the ubiquitous expression we have observed.     

Cloning,expression, and genomic organization of mouse mp29 gene

The convulsions of approximately 25% of epileptics are inadequately controlled by currently available medication; therefore the preparation of new antiepileptic drugs is of great interest. Aryl semicarbazones can be considered a new class of compounds presenting anticonvulsant activity. In addition, they can be orally administered and are more active as anticonvulsants than mephenytoin or phenobarbital. However, one disadvantage of these compounds is their low water solubility. As a strategy to circumvent this problem, a 1:1 inclusion compound of benzaldehyde semicarbazone (BS) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was prepared and characterized. The anticonvulsant activities of the free semicarbazone and of the inclusion compound were evaluated in rats using the maximum electroshock and audiogenic seizures screenings. In both tests the minimum dose of compound necessary to produce activity decreases from 100mg/kg for the free semicarbazone to 35 mg/kg for the inclusion compound, indicating a significant increase in the bio-availability of the drug.