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S Rodríguez de Córdoba

Publications and source records attributed to S Rodríguez de Córdoba.

At least 19 recordsLinked to original sources
PubMed2005

Lafora disease due to EPM2B mutations: a clinical and genetic study.

OBJECTIVE: To study EPM2B gene mutations and genotype-phenotype correlations in patients with Lafora disease. METHODS: The authors performed a clinical and mutational analysis of 25 patients, from 23 families, diagnosed with Lafora disease who had not shown mutations in the EPM2A gene. RESULTS: The authors identified 18 mutations in EPM2B, including 12 novel mutations: 4 nonsense mutations (R265X, C26X, W219X, and E67X), a 6-base pair (bp) microdeletion resulting in a two amino acid deletion (V294_K295del), a 4-bp insertion resulting in a frameshift mutation (S339fs12), and 6 missense mutations (D308A, I198N, C68Y, E67Q, P264H, and D233A). In our data set of 77 families with Lafora disease, 54 (70.1%) tested probands have mutations in EPM2A, 21 (27.3%) in EPM2B, and 2 (2.6%) have no mutations in either gene. The course of the disease was longer in patients with EPM2B mutations vs patients with EPM2A mutations. CONCLUSIONS: Genetic allelic heterogeneity is present in Lafora disease associated with mutations in EPM2B. Patients with mutations in EPM2A and EPM2B express similar clinical manifestation, although patients with EPM2B-associated Lafora disease seem to have a slightly milder clinical course. The lack of mutations in EPM2A and EPM2B in two families could be because of the presence of mutations in noncoding, nontested regions or the existence of an additional gene associated with Lafora disease.

Adolescent↗
PubMed2004

Functional analysis in serum from atypical Hemolytic Uremic Syndrome patients reveals impaired protection of host cells associated with mutations in factor H.

A subgroup of patients with the most severe form of the Hemolytic Uremic Syndrome (HUS) presents mutations in the complement regulatory protein factor H. The functional analyses of the factor H mutant proteins purified from some of these patients have shown a specific defect in the capacity to control complement activation on cellular surfaces. Here, we show that these factor H-related complement regulatory defects can be detected in the patients' serum with a simple hemolytic assay. Data obtained from HUS patients and control individuals indicate that this assay is a useful tool for the molecular diagnosis of factor H-related HUS.

Animals↗
PubMed2001

Clustering of missense mutations in the C-terminal region of factor H in atypical hemolytic uremic syndrome.

Hemolytic-uremic syndrome (HUS) is a microvasculature disorder leading to microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Most cases of HUS are associated with epidemics of diarrhea caused by verocytotoxin-producing bacteria, but atypical cases of HUS not associated with diarrhea (aHUS) also occur. Early studies describing the association of aHUS with deficiencies of factor H suggested a role for this complement regulator in aHUS. Molecular evidence of factor H involvement in aHUS was first provided by Warwicker et al., who demonstrated that aHUS segregated with the chromosome 1q region containing the factor H gene (HF1) and who identified a mutation in HF1 in a case of familial aHUS with normal levels of factor H. We have performed the mutational screening of the HF1 gene in a novel series of 13 Spanish patients with aHUS who present normal complement profiles and whose plasma levels of factor H are, with one exception, within the normal range. These studies have resulted in the identification of five novel HF1 mutations in four of the patients. Allele HF1 Delta exon2, a genomic deletion of exon 2, produces a null HF1 allele and results in plasma levels of factor H that are 50% of normal. T956M, W1183L, L1189R, and V1197A are missense mutations that alter amino acid residues in the C-terminal portion of factor H, within a region--SCR16-SCR20--that is involved in the binding to solid-phase C3b and to negatively charged cellular structures. This remarkable clustering of mutations in HF1 suggests that a specific dysfunction in the protection of cellular surfaces by factor H is a major pathogenic condition underlying aHUS.

Base Sequence↗
PubMed2000

Assessment of the interaction of human complement regulatory proteins with group A Streptococcus. Identification of a high-affinity group A Streptococcus binding site in FHL-1.

Group A Streptococcus (GAS), the most frequent bacterial cause of suppurative infections in humans, expresses on the cell surface M proteins with capacity to bind factor H, FHL-1 and C4b binding protein (C4BP). This has been interpreted as a mechanism developed by this pathogen to decrease phagocytosis by macrophages and polymorphonuclear cells. We report the analysis of the capacity to bind factor H, FHL-1 and C4BP of 69 clinical isolates from 19 different serotypes. We show that strains binding complement regulators (30/69) belong to specific M serotypes. Of these, M18 strains are relatively frequent and interact with all three complement regulators simultaneously. However, the most virulent M1 and M3 strains did not bind complement regulators in our assays. The relevance of the interaction between complement regulators and S. pyogenes was analyzed using different approaches with the conclusion that under physiological conditions only FHL-1 and C4BP bind to streptococci. We show that FHL-1 presents a higher binding affinity for S. pyogenes than factor H because it carries a hydrophobic, high-affinity, GAS binding site in addition to the heparin binding site in SCR7. Using synthetic peptides we provide evidence that the high-affinity GAS binding site in FHL-1 involves the hydrophobic tail (Ser-Phe-Thr-Leu) that distinguishes FHL-1 from factor H.

Amino Acid Sequence↗
PubMed1999

Genomic cloning and characterization of the human homeobox gene SIX6 reveals a cluster of SIX genes in chromosome 14 and associates SIX6 hemizygosity with bilateral anophthalmia and pituitary anomalies.

The Drosophila gene sine oculis (so), a nuclear homeoprotein that is required for eye development, has several homologues in vertebrates (the SIX gene family). Among them, SIX3 is considered to be the functional orthologue of so because it is strongly expressed in the developing eye. However, embryonic SIX3 expression is not limited to the eye field, and SIX3 has been found to be mutated in some patients with holoprosencephaly type 2 (HPE2), suggesting that SIX3 has wide implications in head development. We report here the cloning and characterization of SIX6, a novel human SIX gene that is the homologue of the chick Six6(Optx2) gene. SIX6 is closely related to SIX3 and is expressed in the developing and adult human retina. Data from chick and mouse suggest that the human SIX6 gene is also expressed in the hypothalamic and the pituitary regions. SIX6 spans 2567 bp of genomic DNA and is split in two exons that are transcribed into a 1393-nucleotide-long mRNA. Chromosomal mapping of SIX6 revealed that it is closely linked to SIX1 and SIX4 in human chromosome 14q22.3-q23, which provides clues about the origin and evolution of the vertebrate SIX family. Recently three independent reports have associated interstitial deletions at 14q22.3-q23 with bilateral anophthalmia and pituitary anomalies. Genomic analyses of one of these cases demonstrated SIX6 hemizygosity, strongly suggesting that SIX6 haploinsufficiency is responsible for these developmental disorders.

Amino Acid Sequence↗
PubMed1999

Genomic cloning, structure, expression pattern, and chromosomal location of the human SIX3 gene.

The Drosophila gene sine oculis (so) is a nuclear homeoprotein that is required for eye development. Homologous genes to so, denoted SIX genes, have been found in vertebrates. Among the SIX genes, SIX3 is considered to be the functional homologue of so. To provide insight into the potential implications of SIX3 in human ocular malformations, we have cloned and characterized the human SIX3 gene. In human eye, SIX3 produces a 3-kb transcript that codes for a 332-amino-acid polypeptide that is virtually identical to its mouse and chick homologues. Expression of SIX3 was detected in human embryos as early as 5-7 weeks of gestation and found to be maintained in the eye throughout the entire period of fetal development. At 20 weeks of gestation, expression of SIX3 in the human retina was detected in the ganglion cells and in cells of the inner nuclear layer. The human SIX3 gene spans 4.4 kb of genomic DNA and is split in two exons separated by a 1659-bp intron. SIX3 was mapped to human chromosome 2p16-p21, between the genetic markers D2S119 and D2S288. Interestingly, the map position of human SIX3 overlaps the locations of two dominant disorders with ocular phenotypes that have been assigned to this chromosomal region, holoprosencephaly type 2 and Malattia Leventinese.

Amino Acid Sequence↗
PubMed1999

Expression of the beta-chain of the complement regulator C4b-binding protein in human ovary.

Human C4b-binding protein (C4BP) is an important regulator of the complement system that also binds and inactivates the anticoagulant vitamin K-dependent protein S. These two activities are performed by two distinct polypeptides of 70 kDa and 45 kDa known as alpha and beta chains, respectively. C4BP is present in plasma in various isoforms with different alpha/beta composition. We report here that C4BPbeta, but not C4BPalpha, is expressed in adult human ovary. Expression of C4BPbeta was detected in all ovarian biopsies analyzed (n = 15), independently of age and phase of the menstrual cycle. In situ hybridization and immunostaining analyses on cryostat sections demonstrated expression of C4BPbeta in both regressing corpus luteum and corpus albicans, but not in the follicles, the corpus luteum, the ovary stroma or the vascular cells. In addition, we noted that the expression pattern of the C4BPbeta mRNA resembles that described for the connective tissue that invades the degenerating corpus luteum and causes a progressive fibrosis that gradually converts it into a scar, the corpus albicans. RT-PCR and immunostaining analyses of primary cultures derived from human ovaries demonstrated the presence of fibroblast-like cells that express C4BPbeta. As a whole, these data suggest a role for the C4BPbeta in human ovary during the healing and scar resorption processes that leads to the formation of the corpus albicans and its replacement by ovarian stroma.

Adult↗
PubMed1999

Analysis of alkaptonuria (AKU) mutations and polymorphisms reveals that the CCC sequence motif is a mutational hot spot in the homogentisate 1,2 dioxygenase gene (HGO).

We recently showed that alkaptonuria (AKU) is caused by loss-of-function mutations in the homogentisate 1,2 dioxygenase gene (HGO). Herein we describe haplotype and mutational analyses of HGO in seven new AKU pedigrees. These analyses identified two novel single-nucleotide polymorphisms (INV4+31A-->G and INV11+18A-->G) and six novel AKU mutations (INV1-1G-->A, W60G, Y62C, A122D, P230T, and D291E), which further illustrates the remarkable allelic heterogeneity found in AKU. Reexamination of all 29 mutations and polymorphisms thus far described in HGO shows that these nucleotide changes are not randomly distributed; the CCC sequence motif and its inverted complement, GGG, are preferentially mutated. These analyses also demonstrated that the nucleotide substitutions in HGO do not involve CpG dinucleotides, which illustrates important differences between HGO and other genes for the occurrence of mutation at specific short-sequence motifs. Because the CCC sequence motifs comprise a significant proportion (34.5%) of all mutated bases that have been observed in HGO, we conclude that the CCC triplet is a mutational hot spot in HGO.

Alkaptonuria↗
PubMed1999

Mutational analysis of the HGO gene in Finnish alkaptonuria patients.

Alkaptonuria (AKU), the prototypic inborn error of metabolism, has recently been shown to be caused by loss of function mutations in the homogentisate-1,2-dioxygenase gene (HGO). So far 17 mutations have been characterised in AKU patients of different ethnic origin. We describe three novel mutations (R58fs, R330S, and H371R) and one common AKU mutation (M368V), detected by mutational and polymorphism analysis of the HGO gene in five Finnish AKU pedigrees. The three novel AKU mutations are most likely specific for the Finnish population and have originated recently.

Alkaptonuria↗
PubMed1998

Sequence and structure of the human 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase heart isoform gene (PFKFB2).

6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) is a bifunctional enzyme that catalyzes the synthesis and degradation of Fru-2,6-P2, a key regulator of glycolysis. In mammals, several genes have been found to code for different PFK-2/FBPase-2 isoforms that differ in tissue distribution and enzymatic activities. In the present study, we report the characterization of the PFK-2/FBPase-2 heart isoform gene in humans (PFKFB2), including a full analysis of repetitive sequences and potential transcription binding sites. The genomic sequence of the PFKFB2 gene spans 22,485 bp and contains 15 exons. Heart cDNA analysis shows that PFKFB2 codes for a protein of 505 amino acids with a deduced molecular mass of 58,849 Da. Comparison of the human PFKFB2 gene to the homologous genes in rat and ox outlines a significant conservation of the intron-exon structure, sequence of 5' and 3' flanking regions, and simple sequence repetitive element positions. Most important, the human heart PFK-2/ FBPase-2 protein was found to retain all the important regulatory sites, as well as the catalytic and substrate binding sites identified in the rat and bovine heart isoforms, suggesting that the human enzyme is regulated in a manner similar to that observed in these organisms.

Amino Acid Sequence↗
PubMed1997

A region of allelic imbalance in 1q31-32 in primary breast cancer coincides with a recombination hot spot.

Previous studies have shown that the 1q31-32 region frequently presents allelic imbalance (AI) in various neoplastic diseases, such as breast cancer, medulloblastoma, male germ cell tumors, and renal collecting duct carcinoma, suggesting the presence of a tumor suppressor gene in this location. We used 19 informative microsatellite markers to analyze 33 primary breast tumors for AI in the 1q31-32 region. Our results demonstrate a 10-cM critical region of AI that is present in more than 60% of the tumors. This region is located proximal to the REN locus and is flanked by the CACNL1A3 and D1S2655 markers. Most important, the critical region of AI coincides with a female hot spot of recombination, suggesting a possible correlation between the two regions.

Alleles↗
PubMed1997

The human homogentisate 1,2-dioxygenase (HGO) gene.

Alkaptonuria (AKU; McKusick No. 203500), a rare hereditary disorder of the phenylalanine catabolism, was the first disease to be interpreted as an inborn error of metabolism (A. E. Garrod, 1902, Lancet 2: 1616-1620). AKU patients are deficient for homogentisate 1,2-dioxygenase (HGO; EC 1.13.11.5). This enzymatic deficiency causes homogentisic aciduria, ochronosis, and arthritis. Recently we cloned the human HGO gene and showed that AKU patients carry two copies of a loss-of-function HGO allele. Here we describe the complete nucleotide sequence of the human HGO gene and the identification of its promoter region. The human HGO gene spans 54,363 bp and codes for a 1715-nt-long transcript that is split into 14 exons ranging from 35 to 360 bp. The HGO introns, 605 to 17,687 bp in length, contain representatives of the major classes of repetitive elements, including several simple sequence repeats (SSR). Two of these SSRs, a (CT)n repeat in intron 4 and a (CA)n repeat in intron 13, were found to be polymorphic in a Spanish population sample. The HGO transcription start site was determined by primer extension. We report that sequences from -1074 to +89 bp (relative to the HGO transcription start site) are sufficient to promote transcription of a CAT reporter gene in human liver cells and that this fragment contains putative binding sites for liver-enriched transcription factors that might be involved in the regulation of HGO expression in liver.

Alkaptonuria↗
PubMed1997

A high-resolution map of the regulator of the complement activation gene cluster on 1q32 that integrates new genes and markers.

Sixteen microsatellite markers, including two described here, were used to construct a high-resolution map of the 1q32 region encompassing the regulator of the complement activation (RCA) gene cluster. The RCA genes are a group of related genes coding for plasma and membrane associated proteins that collectively control activation of the complement component C3. We provide here the location of two new genes within the RCA gene cluster. These genes are PFKFB2 that maps 15 kilobases (kb) upstream of the C4BPB gene, and a gene located 4 kb downstream of C4BPA, which seems to code for the 72 000 Mr component of the signal recognition particle (SRP72). Neither of these two genes is related structurally or functionally to the RCA genes. In addition, our map shows the centromere-telomere orientation of the C4BPB/MCP linkage group, which is: centromere-PFKFB2-C4BPB-C4BPA-SRP72-C4BPAL1++ +-C4BPAL2-telomere, and outlines an interval with a significant female-male recombination difference which suggests the presence of a female-specific hotspot(s) of recombination.

Chromosome Mapping↗
PubMed1996

Binding of human complement component C4b-binding protein (C4BP) to Streptococcus pyogenes involves the C4b-binding site.

A key step in the elimination of invading pathogens from the body is the covalent binding of complement proteins C3b and C4b to their surface. However, many pathogens have evolved mechanisms to avoid the complement system of the host. Understanding how these mechanisms work may lead to more efficacious forms of therapy. Here we provide an insight into the molecular basis of how Streptococcus pyogenes binds human plasma C4b-binding protein (hC4BP), a complement regulatory molecule that may decrease C3b and C4b deposition on the streptococcal surface. We show that streptococcal surface molecules bind to a site on hC4BP that is indistinguishable from the C4b binding site. This site involves multiple binding surfaces that span short consensus repeats 1 to 3 of the alpha-chain of hC4BP. We propose that hC4BP is bound to the bacterial surface because the streptococcal surface molecules involved in the interaction mimic human C4b epitopes.

Animals↗
PubMed1996

Promoter region of the human gene coding for beta-chain of C4b binding protein. Hepatocyte nuclear factor-3 and nuclear factor-I/CTF transcription factors are required for efficient expression of C4BPB in HepG2 cells.

Differential expression of the human genes coding for the alpha and beta polypeptides of the human C component C4b binding protein (C4BP) modulates the levels of C4BP molecules containing C4BP beta polypeptides, providing a mechanism to avoid the potential harmful effects of elevated concentrations of C4BP beta in plasma. To understand how the expression of the C4BPB gene is controlled, we have examined, in the major promoter of the human C4BP B gene, potential regulatory elements. A region from nucleotide -126 to +25 was able to drive high expression of a reporter gene in the human hepatoma cell line HepG2. A small subfragment of this region (from -126 to -90) is responsible for more than 90% of the promoter activity. Electrophoretic mobility shift assays revealed that transcription factors of the hepatocyte nuclear factor-3 (HNF-3) and nuclear factor-I (NFI/CTF) families were able to bind to this region in a sequence-specific manner. We have characterized binding sites for these transcription factors and determined their relative contribution to the activity of the C4BPB promoter. The results suggest that cooperative interaction between HNF-3 and NF-I/CTF is required to obtain a full C4BPB promoter activity. Comparison of the structures of the C4BPA and C4BPB promoters reveals significant differences that could explain the differential transcription of the C4BP alpha and C4BP beta polypeptides during the acute phase response.

Base Sequence↗