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J Ragoussis

Publications and source records attributed to J Ragoussis.

At least 37 records · Page 2Linked to original sources
PubMed1998

A serpin gene cluster on human chromosome 6p25 contains PI6, PI9 and ELANH2 which have a common structure almost identical to the 18q21 ovalbumin serpin genes.

The human genes encoding the "ovalbumin" subgroup of closely related serine proteinase inhibitors (serpins) are located at 18q21.3 and 6p25. Those at 6p25 include proteinase inhibitor 6 (PI-6; gene symbol PI6), proteinase inhibitor 9 (PI-9; gene symbol PI9) and monocyte neutrophil elastase inhibitor (M/NEI; gene symbol ELANH2). Here we describe the fine mapping of these genes to a 200-kb region of chromosome 6 that includes the markers WI-8835 and D6S1338, and the establishment of the gene order: tel-PI6-PI9-ELANH2-cen. PI6 and ELANH2 are transcribed towards the telomere, and structural analysis shows that PI6 and PI9 are organized identically, having seven exons and six introns. PI6 and PI9 are almost identical in structure to the ovalbumin serpin genes at 18q21.3. The 18q21.3 genes have an extra exon and intron, otherwise all the other exon/intron boundaries are conserved between the two groups. These results represent the first detailed map of the chromosome 6 serpin gene cluster, and demonstrate that although they are very closely related, the 6p25 and 18q21-->q23 ovalbumin serpin genes form two structurally distinct groups. These findings do not support a previously proposed model for evolution of the clusters which invoked an inter-chromosomal duplication of the entire 6p25 group to 18q21.3.

Chromosome Mapping↗
PubMed1997

Fine mapping of 39 ESTs on human chromosome 6p23-p25.

Loci conferring susceptibility to schizophrenia, coeliac disease, and orofacial clefting have been assigned to the 6p23-p25 region of human chromosome 6. To facilitate the identification of candidate genes we have sublocalized and ordered 39 ESTs assigned to this interval by radiation hybrid mapping. This was achieved by generating PAC contigs containing the ESTs, genetic markers, and random STSs. For full integration into previously published data a single YAC contig spanning 6p23-p25 was used to unambiguously order the PAC contigs and ESTs along the chromosome. The majority of the ESTs (31/39) were positioned in the 6p23-p24 interval at the proximal half of the map, and of these 8 are located within a single PAC clone. The order of known genes in this region is cen-CD83-ZNF40-EDN1-(GCNT2, CAPZB)-TFAP2-BMP6-DSP-tel.

Chromosome Mapping↗
PubMed1997

Generation of novel human MHC class II mutant B-cell lines by integrating YAC DNA into a cell line homozygously deleted for the MHC class II region.

The human B lymphoblastoid cell line (LCL) 721.174 sustains a large homozygous deletion in the major histocompatibility complex (MHC) class II region that results in an absence of DQ and DR molecules as well as a deficiency in the assembly and transport of class I molecules to the cell surface. The deleted genes include the transporters associated with antigen processing TAP1 and TAP2, DMA and DMB which are involved in editing class II bound peptides, and four genes whose roles in antigen processing are unclear; the low mass polypeptide genes LMP2 and LMP7, and DNA and DOB. To study this region we have integrated into 721.174 two overlapping yeast artificial chromosome (YAC) clones which cover the interval LMP2-DRA inclusive. Three clones (11.2A1.1, 4D1D10.1 and 4D1D10.2), containing complete copies of the transfected YAC, produced varying levels of mRNA from the LMP, TAP, DQ and DR genes and corresponding levels of LMP and TAP protein. Class I cell surface expression was restored in 11.2A1.1 and 4D1D10.1, as was DR expression in both 4D1D10 transfectants. These studies demonstrate the feasibility of introducing large groups of functional genes back into human lymphoblastoid cells sustaining deletions, with full restoration of biological function. The procedure could be exploited in order to restore all but one gene covered by the deletion, effectively producing a single gene defect. This could be used to introduce copies of genes engineered to contain mutations and to study cis regulatory elements at some distance from the chosen loci.

Amino Acid Sequence↗
PubMed1996

A detailed investigation of two cases exhibiting characteristics of the 6p deletion syndrome.

Deletions of the short arm of chromosome 6 are relatively rare, only 16 cases having been described in the literature so far. Here we present a detailed investigation by fluorescence in situ hybridisation of two further cases with different but overlapping interstitial deletions involving 6p22, 6p23 and 6p24. The main features involved are craniofacial malformations, heart and kidney defects, mental retardation/developmental delay, hypotonia and hydrocephalus. By using 36 yeast artificial chromosome and cosmid clones from a contig covering 6p22.3-6p25 and other probes with defined cytogenetic locations within 6p21-6p22 we have precisely localised the breakpoints involved in each of the cases, estimated the sizes of the deleted regions and defined the region that is hemizygously deleted in both cases.

Abnormalities, Multiple↗
PubMed1995

Evidence of a locus for orofacial clefting on human chromosome 6p24 and STS content map of the region.

Orofacial clefting is genetically complex, no single gene being responsible for all forms. It can, however, result from a single gene defect either as part of a syndrome (e.g. van der Woude syndrome, Treacher-Collins syndrome, velo-cardio-facial syndrome) or as an isolated phenotypic effect (e.g. X-linked cleft palate; non-syndromic, autosomal dominant orofacial clefting). Several studies have suggested that chromosome 6p is a candidate region for a locus involved in orofacial clefting. We have used YAC clones from contigs in 6p25-p23 to investigate three unrelated cases of cleft lip and palate coincident with chromosome 6p abnormalities. Case 1 has bilateral cleft lip and palate and a balanced translocation reported as 46,XY,t(6,7)(p23;q36.1). Case 2 has multiple abnormalities including cleft lip and palate and was reported as 46,XX,del(6)(p23;pter). Case 3 has bilateral cleft lip and palate and carries a balanced translocation reported as 46,XX,t(6;9)(p23;q22.3). We have identified two YAC clones, both of which cross the breakpoint in cases 1 and 3 and are deleted in case 2. These clones map to 6p24.3 and therefore suggest the presence of a locus for orofacial clefting in this region. The HGP22 and AP2 genes, potentially involved in face formation, have been found to flank this region, while F13A maps further telomeric in 6p24.3/25.

Abnormalities, Multiple↗
PubMed1995

An integrated map of human chromosome 6p23.

The human chromosomal band 6p23 is a Giemsa-negative (light) band that may be expected to be relatively gene rich. The genes for spinocerebellar ataxia type 1 (SCA1), guanosine monophosphate reductase (GMPR), DEK involved in a subtype of acute myeloid leukemia (AML), and the folate-sensitive fragile site FRA6A, have already been mapped to 6p23. Recent linkage data have suggested evidence for a susceptibility locus for schizophrenia in the region. We have constructed a single YAC contig of approximately 100 clones spanning the entire 6p23 band from 6p22.3 to 6p24.1 and covering 7.5-8.5 Mb of DNA. The YAC contig contains 55 markers including genetically mapped STSs, physically mapped STSs, anonymous STSs, anonymous ESTs, and ESTs from the genes mapped to the region. The order of the genetically mapped STSs is consistent with their order in the contig and some of the markers not resolved on the genetic map have been resolved by the YACs. Four of the YACs from 6p23 and covering approximately 3 Mb of DNA have been used to isolate approximately 300 cosmids from a flow-sorted human chromosome 6 cosmid library, which have been organized into pockets. The proposed susceptibility locus for schizophrenia is most closely linked to D6S260, which is located within the YAC contig along with genetic markers < or = 5 cM on either side. Therefore, the presented materials are valuable reagents for characterization of the genomic region implicated in schizophrenia.

Base Sequence↗
PubMed1993

Characterization and mapping of the human SOX4 gene.

The SOX genes comprise a large family related by homology to the HMG-box region of the testis-determining gene SRY. We have cloned and sequenced the human SOX4 gene. The open reading frame encodes a 474 amino acid protein, which includes an HMG-box. The non-box sequence is particularly rich in serine residues and has several polyglycine and polyalanine stretches. With somatic cell hybrids, human SOX4 has been mapped to Chromosome (Chr) 6p distal to the MHC region. There is no evidence for clustering of other members of the SOX1, -2, and -3 or SOX4 gene families around the SOX4 locus.

Amino Acid Sequence↗
PubMed1993

New vector for transfer of yeast artificial chromosomes to mammalian cells.

A modification vector has been constructed to facilitate the transfer of yeast artificial chromosomes (YACs) to mammalian cells in culture by targeting a dominant selectable marker (G418 resistance) to the right arm of pYAC4 clones. The ADE2 gene is used for yeast selection with consequent disruption of the URA3 gene, allowing direct modification of YACs within the common host strain AB1380, and providing a simple test for correct targeting. This vector has been tested by modification of a 550-kb YAC containing part of the human MHC class II region and transfer to CHO cells by protoplast fusion. Analysis of 15 independent G418-resistant CHO lines obtained following fusion suggests the majority contain a complete YAC with moderate amplification in some lines.

Animals↗
PubMed1993

Frequent loss of heterozygosity on chromosome 6 in human ovarian carcinoma.

Investigation of genetic changes in tumours by loss of heterozygosity (LOH) is a powerful technique for identifying chromosomal regions that may contain tumour suppressor genes. LOH has been described on chromosome 6 in ovarian carcinoma using restriction fragment length polymorphism analysis with a small number of probes. We studied 29 ovarian carcinomas with 19 probes mapping to chromosome 6. Sixteen of the 29 tumours showed LOH on 6q (55%). Of these 16, 63% showed loss of all informative markers on that arm. One tumour showed loss of 6q24-qter, localising the putative tumour suppressor gene to that region. Loss on 6p was 28% overall. However, using three dinucleotide repeat primer pairs from 6p to study LOH in seven selected tumours, LOH was demonstrated at both 6p22.3-pter and at 6p12-6p22. These results confirm that 6q harbours a tumour suppressor gene of relevance to ovarian carcinoma and suggest that there may also be a similar gene(s) on 6p. By Southern analysis, there was no evidence of genomic rearrangements of the oestrogen receptor gene, located at 6q25.1. LOH on 6q was more common in high than low grade tumours. The relevance of our findings to previous work in ovarian cancer and other solid tumours is discussed.

Chromosome Deletion↗