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H Vissing

Publications and source records attributed to H Vissing.

At least 37 records · Page 2Linked to original sources
PubMed1994

Negative cooperativity in the insulin-like growth factor-I receptor and a chimeric IGF-I/insulin receptor.

Insulin and insulin-like growth factor-I (IGF-I) share a spectrum of metabolic and growth-promoting effects, mediated through homologous receptors that belong to the tyrosine kinase family. The dissociation rate of insulin from its receptor is affected by negative cooperativity, i.e. accelerates with increased receptor occupancy. The dose-response curve for the acceleration of tracer dissociation by unlabeled insulin has a distinct bell-shaped curve, with a progressive slowing down at insulin concentrations greater than 100 nM. The kinetics of the IGF-I interaction with its receptor has not been studied in such detail. In the present work, we report that while the IGF-I receptor exhibits negative cooperativity like the insulin receptor, the concentration dependence of the dissociation kinetics is distinct from that of native human insulin by not being bell-shaped, but monophasic like that of insulin analogues mutated at the hexamer-forming surface; it is changed to an insulin-type curve by substitution of IGF-I receptor's sequence including residues 382-565 with the homologous insulin receptor domain. The data suggest that like insulin, IGF-I has a bivalent binding mode and crosslinks two distinct areas of the two alpha subunits that are close, but distinct from the equivalent insulin receptor binding sites.

Arteries↗
PubMed1993

Mutation of arginine 86 to proline in the insulin receptor alpha subunit causes lack of transport of the receptor to the plasma membrane, loss of binding affinity and a constitutively activated tyrosine kinase in transfected cells.

We have investigated the role of Ser 85 and Arg 86 of the human insulin receptor (HIR) in insulin binding and tyrosine kinase activity by mutational analysis. Four mutant cDNAs were created (R86P, R86N, S85T+R86N, S85W+R86K) and stably transfected into BHK cells. R86P-HIR was also transiently expressed in 293 cells. Only the R86P receptor had substantially altered properties: lack of transport to the plasma membrane, loss of insulin binding, a constitutively activated autophosphorylation and tyrosine kinase, and an incomplete processing. Some of these alterations mimic those reported for the insulin receptor of the leprechaun Atl, which has a homozygous R86P mutation (Longo, N., et al, Biochem. Biophys. Res. Commun., 167, 1229, 1990; Clin. Res., 40, 2, 329, 1992).

Animals↗
PubMed1993

A zinc-finger gene ZNF141 mapping at 4p16.3/D4S90 is a candidate gene for the Wolf-Hirschhorn (4p-) syndrome.

Chromosomal aneusomy is a major cause of reproductive wastage and congenital malformations in man. Zinc finger encoding genes would be good candidates for being involved in the multiple developmental defects associated with chromosomal aneusomy--by virtue of their role as transcriptional regulators, their abundance in the genome and their known association with specific developmental disorders. We have isolated and mapped a zinc finger encoding cDNA (ZNF141) of the C2-H2/KRAB subfamily to the 4p- (Wolf-Hirschhorn) syndrome (WHS) chromosome region. ZNF141 mapped to the distal end of the 2.2 Mb smallest region of deletion overlap of WHS, 300 kb from the 4p telomere on cosmid CD1 defining the anonymous locus D4S90. ZNF141 was expressed ubiquitously at low levels in the analysed tissue. The identification of a candidate gene for a chromosomal aneusomy syndrome belonging to a class of evolutionary conserved genes will provide options for studying its normal and abnormal expression during mammalian embryogenesis.

Abnormalities, Multiple↗
PubMed1993

Deletion mapping of chromosome 3p in human uterine cervical cancer.

Deletion mapping of chromosome 3p was performed on 47 cases of human uterine cervical cancer using 24 polymorphic DNA markers including five inter-Alu DNA markers and two NotI-boundary cosmid markers obtained in our laboratory. The most likely order of these 24 polymorphic DNA markers was determined as being cen-[D3S4, H8]-D3S693-D3S659-D3S30-D3S687-[D3S2, UR9, UR47]-J36-J17-GNAI2B-D3F15S2-D3S643- D3S32-D3S23-D3S686-H35-UR189-D3S685-D3S 11 - D3S12-THRB-D3S22-pter, based on the data from radiation hybrid mapping genetic linkage analysis and in situ hybridization. Loss of heterozygosity (LOH) at one or more loci on chromosome 3p was detected in 21 of 47 cases (45%). Four tumors showed partial or interstitial deletions, and the common region of LOH in these tumors was 3p13-p21.1 between the D3S30 marker and the D3S2 marker. Candidates for tumor-suppressor genes, APEH, D8, GNA12B, ZNF35, RARB, THRB and RAFI, were all mapped outside of the common region in uterine cervical cancer. However, this region is commonly deleted in carcinoma of the lung, breast and kidney, and encompasses the breakpoint of the (3;8) translocation in hereditary renal cell carcinoma. This result indicates the presence of a novel tumor-suppressor gene in the region of 3p13-p21.1, which is involved in the development of several human cancers.

Base Sequence↗
PubMed1992

Identification of determinants that confer ligand specificity on the insulin receptor.

We have previously shown, using truncated soluble recombinant receptors, that substituting the 62 N-terminal amino acids of the alpha subunit from the insulin-like growth factor I receptor (IGFIR) with the corresponding 68 amino acids from the insulin receptor (IR) results in a chimeric receptor with an approximately 200-fold increase in affinity for insulin and only a 5-fold decrease in insulin-like growth factor I (IGFI) affinity (Kjeldsen, T., Andersen, A. S., Wiberg, F. C., Rasmussen, J. S., Schäffer, L., Balschmidt, P., Møller, K. B., and Møller, N. P. H. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 4404-4408). We demonstrate that these 68 N-terminal amino acids of the IR also confer insulin affinity on the intact IGFI holoreceptor both in the membrane-bound state and when solubilized by Triton X-100. Furthermore, this domain can be subdivided into two regions (amino acids 1-27 and 28-68 of the IR alpha subunit) that, when replacing the corresponding IGFIR sequences, increases the insulin affinity of truncated soluble receptor chimeras 8- and 20-fold, respectively, with only minor effects on the IGFI affinity. Within the latter of these two regions, we found that amino acids 38-68 of the IR, representing 13 amino acid differences from IGFIR, confer the same 20-fold increase in insulin affinity on the IGFIR. Finally, the amino acids from position 42 to 50 are not responsible for this increase in insulin affinity. We thus propose that at least two determinants within the 68 N-terminal amino acids of the insulin receptor are involved in defining the ligand specificity of the insulin receptor, and that one or a combination of the remaining seven amino acid differences between position 38 and 68 are involved in conferring insulin affinity on the insulin receptor.

Amino Acid Sequence↗
PubMed1991

Multiexon deletion in the procollagen III gene is associated with mild Ehlers-Danlos syndrome type IV.

We have characterized a deletion of approximately 9 kilobases which spans from intron 33 to exon 48 of one pro-alpha 1 (III) collagen allele in a patient with Ehlers-Danlos syndrome type IV. The mutation results in the production of an in-frame species of mRNA which lacks the sequences corresponding to residues 595-1,008 of the triple-helical domain. Thus, half of the pro-alpha 1 (III) chains synthesized by the patient's fibroblasts are nearly 30% shorter than normal. The procollagen III molecules composed of either three normal length or three shortened chains are thermally stable and efficiently secreted. In contrast, the procollagen III molecules that contain one or two shortened chains are unstable and are not secreted. Failure to secrete unstable molecules and a residual functional role of the shortened but stable homotrimers may explain the somewhat milder phenotype of this individual compared with that of another Ehlers-Danlos type IV patient bearing a deletion of similar size in the amino-terminal portion of the alpha 1 (III) collagen chain.

Chromosome Deletion↗
PubMed1991

Characterization of a large deletion associated with a polymorphic block of repeated dinucleotides in the type III procollagen gene (COL3A1) of a patient with Ehlers-Danlos syndrome type IV.

Ehlers-Danlos syndrome type IV (EDS IV) is an autosomal dominant condition characterized by extreme fragility of skin, blood vessels, intestine, gravid uterus, and lungs. The phenotype is accounted for by mutations affecting the integrity and/or synthesis of the precursor procollagen molecules of type III collagen. In this article, we report the elucidation of the molecular defect in an EDS IV patient whose type III collagen was previously found to be structurally abnormal. We utilized PCR in a two-step process involving first the localization of the mutation in the mRNA and then the characterization of the defect in the gene. The results established the patient's heterozygosity for a genomic deletion of about 7.5 kb which eliminates 1,026 nucleotides of coding sequences in the message. The mutation arose as a result of an exon-to-intron recombination. The deleted segment extends from the 13th nucleotide of exon 9 to within a DNA sequence of intron 24, which is composed of a series of dinucleotide repeats. Using PCR, we tested the polymorphic nature of this DNA element on several unrelated individuals. Analysis of amplified genomic products of 45 chromosomes recognized at least four distinct allelic forms that display frequencies ranging from 5% to 61%. Mendelian segregation of three of the four alleles was established by the same method in a 3-generation family.

Alleles↗
PubMed1990

Alternative splicing of the human alpha 2(VI) collagen gene generates multiple mRNA transcripts which predict three protein variants with distinct carboxyl termini.

We recently reported the isolation and sequencing of two classes of human alpha 2(VI) collagen cDNA clones which share common sequences for the first two-thirds of the molecule but contain a different sequence of either 607 or 887 base pairs at their 3' ends (Chu, M.-L., Pan, T.-C., Conway, D., Kuo, H.-J., Glanville, R. W., Timpl, R., Mann, K., and Deutzmann, R. (1989) EMBO J. 8, 1939-1946). In the present study, we report the sequence of another cDNA clone, which is identical to one class of the previously isolated cDNAs except for a 293-base pair insertion between the common and variable regions. Together, the different classes of cDNAs, referred to as the alpha 2C2, alpha 2C2a, and alpha 2C2a' predict three variant alpha 2 chains of type VI collagen with carboxyl globular domains of 429, 328, and 238 amino acid residues, respectively. In order to explore the mechanisms by which the variations are generated, we isolated and characterized the 3' end of the human alpha 2(VI) collagen gene. The carboxyl globular domain was found to be encoded by six exons which appear to delineate its structural subdomains. The exon/intron arrangement clearly demonstrated that the cDNA variants arose from alternative splicing events by mutually exclusive utilization of the last two exons in conjunction with the selective usage of an internal splice acceptor site in the penultimate exon. The presence of the corresponding mature mRNA transcripts (3.2-3.5 kilobase pairs (kb] in human fibroblasts was shown by Northern blot hybridization, S1 nuclease protection assay, and the polymerase chain reaction. The results indicated that the alpha 2C2 mRNA is the major species, whereas the alpha 2C2a and alpha 2C2a' are the minor forms. Northern blot hybridization also revealed an alpha 2(VI) collagen mRNA of 6.0 kb. This mRNA retained a 2.3-kb intron located between the two alternatively spliced exons and predicted a translational product that is the same as the alpha 2C2a variant.

Amino Acid Sequence↗
PubMed1989

Glycine to serine substitution in the triple helical domain of pro-alpha 1 (II) collagen results in a lethal perinatal form of short-limbed dwarfism.

Previous biochemical studies on cartilage tissue from a proband with Type II achondrogenesis-hypochondrogenesis (Godfrey, M., and Hollister, D. W. (1988) Am. J. Hum. Genet. 43, 904-913) indicated heterozygosity for a structural abnormality in the triple helical domain of pro-alpha 1 (II) collagen. Here we demonstrate that the mutation in the type II procollagen gene is a single base change that converts the codon for glycine (GGC) at amino acid 943 of the alpha 1 (II) chain to a codon for serine (AGC). The substitution disrupts the invariant Gly-X-Y structural motif necessary for perfect triple helix formation and leads to extensive overmodification, intracellular retention, and reduced secretion of type II collagen. These findings confirm the proposal that new dominant mutations in the type II procollagen gene may account for some cases of Type II achondrogenesis-hypochondrogenesis. Since recent studies (Lee, B., Vissing, H., Ramirez, F., Rogers, D., and Rimoin, D. (1989) Science 244, 978-980) have identified a dominantly inherited type II procollagen gene deletion in a non-lethal form of skeletal dysplasia, namely spondyloepiphyseal dysplasia, the data more generally demonstrate that different type II procollagen gene mutations eventuate in a wide and diverse spectrum of clinical phenotypes.

Amino Acid Sequence↗
PubMed1989

Identification of the molecular defect in a family with spondyloepiphyseal dysplasia.

Spondyloepiphyseal dysplasias (SED) are a heterogeneous group of inherited disorders characterized by disproportionate short stature and pleiotropic involvement of the skeletal and ocular systems. Evidence has suggested that SED may result from structural defects in type II collagen. To confirm the validity of this hypothesis, the structure of the "candidate" type II collagen gene (COL2A1) has been directly examined in a relatively large SED family. Coarse scanning of the gene by Southern blot hybridization identified an abnormal restriction pattern in one of the affected members of the kindred. Analysis of selected genomic fragments, amplified by the polymerase chain reaction, precisely localized the molecular defect and demonstrated that all affected family members carried the same heterozygous single-exon deletion. As a consequence of the mutation, nearly 90 percent of the assembled type II collagen homotrimers are expected to contain one or more procollagen subunits harboring an interstitial deletion of 36 amino acids in the triple helical domain.

Amino Acid Sequence↗
PubMed1989

Organization of the exons coding for pro alpha 1(II) collagen N-propeptide confirms a distinct evolutionary history of this domain of the fibrillar collagen genes.

The organization of the exons coding for the N-terminal portion of human type II procollagen has been determined. Aside from inferring the previously unknown primary structure of type II N-propeptide, this study has revealed that this coding domain of the gene exhibits an organization uniquely distinct from those of type I and type III collagens. This finding substantiates the notion that the N-propeptide coding domains of the fibrillar collagen genes evolved under less stringent selection than those encoding the C-propeptide and triple helical regions.

Amino Acid Sequence↗