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A Palsdottir

Publications and source records attributed to A Palsdottir.

14 recordsLinked to original sources
PubMed1990

Structure and expression of the human cystatin C gene.

The structural organization of the gene for the human cysteine-proteinase inhibitor cystatin C was studied. Restriction-endonuclease digests of human genomic DNA hybridized with human cystatin C cDNA and genomic probes produced patterns consistent with a single cystatin C gene and, also, the presence of six closely related sequences in the human genome. A 30 kb restriction map covering the genomic region of the cystatin C gene was constructed. The positions of three polymorphic restriction sites, found at examination of digests of genomic DNA from 79 subjects, were localized in the flanking regions of the gene. The gene was cloned and the nucleotide sequence of a 7.3 kb genomic segment was determined, containing the three exons of the cystatin C structural gene as well as 1.0 kb of 5'-flanking and 2.0 kb of 3'-flanking sequences. Northern-blot experiments revealed that the cystatin C gene is expressed in every human tissue examined, including kidney, liver, pancreas, intestine, stomach, antrum, lung and placenta. The highest cystatin C expression was seen in seminal vesicles. The apparently non-tissue-specific expression of this cysteine-proteinase inhibitor gene is discussed with respect to the structure of its 5'-flanking region, which shares several features with those of housekeeping genes.

Amino Acid Sequence↗
PubMed1990

Analysis of the C4 genes in baleen whales using a human cDNA probe.

We have used a human C4 cDNA probe to investigate the complement component C4 gene in four members of the family Balaenopteridae: fin whale (Balaenoptera physalus), sei whale (B. borealis), minke whale (B. acutorostrata), and bryde's whale (B. edeni). Restriction mapping of genomic DNA from the first three species suggests the presence of only one locus in these species, and also shows that the C4 genes in the three species are very similar. We have used 14 restriction endonucleases to investigate the restriction fragment length polymorphism (RFLP) of fin whales, 13 enzymes for sei whales, and 8 enzymes for the minke whale. No polymorphism was seen in DNA from the five minke whale samples, but Rsa I and Taq I restriction enzymes gave polymorphism in fin and sei whales whereas Hind III and Msp I restriction enzymes showed polymorphism in sei whales only. Only one bryde's whale sample was available for investigation. The study of DNA available from mother-fetus pairs from the two polymorphic species demonstrated a simple, two-allele transmission of RFLP alleles.

Animals↗
PubMed1989

The saga of cystatin C gene mutation causing amyloid angiopathy and brain hemorrhage--clinical genetics in Iceland.

Firstly, we review investigations of hereditary cystatin C amyloid angiopathy, which is caused by a mutation in the cystatin C gene. Symptoms of brain haemorrhages, which lead to death in young adults, are the hallmark of this disorder. The mutation can now be detected by the RFLP method using Alu I restriction enzyme and cystatin C cDNA probe. Secondly, we give an overview of other clinical genetic studies in Iceland with emphasis on activities initiated or sponsored by the Genetical Committee of the University of Iceland. The list of references covers most publications on genetic studies of Icelanders.

Amyloidosis↗
PubMed1989

Study of restriction fragment length polymorphism in the cystatin C gene of elderly patients with dementia and aged Down's syndrome patients.

Using a full length cystatin C cDNA probe and the Alu I restriction enzyme a total of 33 patients with senile dementia, Alzheimer type and 31 Down's syndrome patients have been investigated for the presence of the 630 bp Alu I restriction fragment length polymorphism in the cystatin C gene detected in Icelandic patients with hereditary cystatin C amyloid angiopathy. Results showed that all the patients had normal cystatin C fragment length of 600 bp.

Adult↗
PubMed1989

Mutation in the cystatin C gene causes hereditary brain hemorrhage.

Hereditary cystatin C amyloid angiopathy (HCCAA) is an autosomal dominant disorder leading to massive brain hemorrhage and death in young adults (Jensson et al., 1987). A variant of a potent inhibitor of cysteine proteinases, cystatin C (Barrett et al., 1984), is deposited as amyloid fibrils in the cerebral arteries of the patients (Ghiso et al., 1986). We have used the full length cystatin C cDNA probe (Abrahamson et al., 1987) to demonstrate a mutation in the codon for leucine at position 68, which abolishes an Alu I restriction site in cystatin C gene of the HCCAA patients. The Alu I marker has been used to show that this mutation is transmitted only in the affected members in all eight families investigated, proving that the mutated cystatin C gene causes HCCAA. This DNA marker will be useful for the diagnosis of HCCAA in patients, asymptomatic affected individuals and also for pre-natal diagnosis. HCCAA is the first human disorder known to be caused by an abnormal gene for a cysteine proteinase inhibitor.

Amyloidosis↗
PubMed1988

Mutation in cystatin C gene causes hereditary brain haemorrhage.

Hereditary cystatin C amyloid angiopathy (HCCAA) is an autosomal dominant disorder in which a cysteine proteinase inhibitor, cystatin C, is deposited as amyloid fibrils in the cerebral arteries of patients and leads to massive brain haemorrhage and death in young adults. A full length cystatin C cDNA probe revealed a mutation in the codon for leucine at position 68 which abolishes an Alu I restriction site in the cystatin C gene of HCCAA patients. The Alu I marker has been used to show that this mutation is transmitted only in affected members of all eight families investigated, and that the mutated cystatin C gene causes HCCAA.

Cerebral Hemorrhage↗
PubMed1987

Gene organization of haplotypes expressing two different C4A allotypes.

The gene organization of C4 haplotypes expressing two different C4A allotypes with a C4B null allele (C4A3A2BQ0 and C4A3A6BQO) was studied using Southern blot analysis with cDNA probes and restriction enzymes which give C4A and C4B locus-specific restriction fragments. These haplotypes were shown to have both a C4A and a C4B locus present, suggesting that the C4B locus expresses a C4A protein. The finding of a 21-OH A and a 21-OH B gene on the C4A3A6BQO haplotype further suggests that this haplotype has the common gene organization C4A, 21-OH A, C4B, 21-OH B. A model explaining C4 null alleles on haplotypes found to have two C4 loci is presented.

Alleles↗
PubMed1987

Heterogeneity of human C4 gene size. A large intron (6.5 kb) is present in all C4A genes and some C4B genes.

In this article we present a study showing that the human C4 genes differ in length because of the presence or absence of a 6.5 kb intron near the 5' end of the gene. DNA from individuals of known HLA, factor B, and C4 haplotypes was analyzed for restriction fragment length polymorphism (RFLP) by Southern blot analysis with C4-specific cDNA probes. The RFLP patterns obtained showed that the C4 genes are either 22.5 kb or 16 kb in length. They are referred to as long and short C4 genes, respectively. A population study was carried out to examine the distribution of the gene size according to C4 allotypes and haplotypes. Long C4 genes included all C4A genes studied and also some C4B allotypes, e.g., B1 on most C4 A3B1 haplotypes. Similarly, C4B null genes were found to be of the long form. Other C4B allotypes tested were found to be coded for by short C4 genes, including B2, B1 in C4 A6B1 and C4 AQOB1 (with a single C4B gene haplotype).

Complement C4↗
PubMed1986

Molecular genetics of the fourth component of human complement.

The fourth component of human complement is encoded by two separate, but closely linked, loci, C4A and C4B, that have been positioned within the class III region of the HLA complex. While the two isotypes vary by only six amino acid residues, they differ significantly in haemolytic activity. Both loci are considerably polymorphic and this may be biologically relevant to ensure interaction with a wide range of pathogens. The number of C4 genes expressed is polymorphic as null alleles, total deficiency and duplication has been shown based on protein studies. Southern analysis of 24 different haplotypes with either C4A or C4B null alleles using the C4 probes showed that three of the null alleles were due to deleted genes but the majority appeared normal. A cosmid library was prepared from DNA of one of the deleted haplotypes and the region of deletion analysed by restriction mapping.

Alleles↗
PubMed1985

Deletion of complement C4 and steroid 21-hydroxylase genes in the HLA class III region.

Molecular maps have been prepared of the HLA region on human chromosome 6 that includes the complement C4 and steroid 21-hydroxylase genes (21-OH), using DNA of individuals deficient (QO) in either of the two forms C4A or C4B. In all, 18 haplotypes with C4A QO were examined by Southern analysis and two had deletions of 28-30 kb that included both the C4A and 21-OHA genes. Of six C4B QO haplotypes, one had a deletion that included both the C4B and 21-OHA genes. Thus, some of the C4 null alleles are due to deletion of the gene but the majority in this sample are not. Deletion occurred in two common haplotypes suggesting that in the population as a whole, C4A deficiency is due to deletion in about one-half the C4A QO haplotypes. As duplication of C4A or C4B genes does occur, the possibility that unequal cross-over could explain the C4 deletion was examined by preparing cosmid clones from the DNA of an individual typed C4A QO. A cloned genomic fragment containing the single C4B gene was isolated and found to be similar to the homologous region of a cosmid from a normal individual carrying a C4A gene. This suggests that if a cross-over has occurred it is in a region where the two genes are identical. The biological significance of the rather frequent occurrence in the population of haplotypes with C4A or C4B deletion together with the accompanying deletion of the 21-OHA gene is discussed.

Alleles↗
PubMedDate not supplied

Species hybridization between a female blue whale (Balaenoptera musculus) and a male fin whale (B. physalus): molecular and morphological documentation.

In 1986 a large, pregnant, female balaenopterid whale was caught in Icelandic waters. The animal had morphological characteristics of both the blue and the fin whale. Molecular analyses of the whale showed that it was a hybrid between a female blue whale and a male fin whale. The descent of the species hybrid was established without access to either parental specimen. Analysis of the fetus showed that it had a blue whale father. The present report of species hybridization between the two largest cetacean species, the blue and the fin whale, documents the occurrence of cetacean species hybridization in the wild. It is also the first example of any cetacean hybridization giving rise to a fertile offspring.

Animals↗