Biomedical subjects

K J Robson

Publications and source records attributed to K J Robson.

81 records · Page 5Linked to original sources

PubMed1984

The PKU locus in man is on chromosome 12.

Classical phenylketonuria (PKU) is a typical example of inborn errors in metabolism and is characterized by a complete lack of the hepatic enzyme phenylalanine hydroxylase, which normally converts phenylalanine to tyrosine. The genetic disorder causes impairment of postnatal brain development, resulting in severe mental retardation in untreated children. The disease is transmitted as an autosomal recessive trait and has a collective prevalence of about one in 10,000 among Caucasians, so that 2% of the population are carriers of the PKU trait. We have recently reported the cloning of human phenylalanine hydroxylase cDNA and that the human chromosomal phenylalanine hydroxylase gene is encoded by a unique DNA sequence. Using the human phenylalanine hydroxylase cDNA clone to analyze a clonal human/mouse hybrid cell panel by Southern hybridization, the phenylalanine hydroxylase gene has been assigned to human chromosome 12. Since the hypothesis that classical PKU is caused by structural mutations in the phenylalanine hydroxylase gene itself rather than through some transregulatory mechanisms has recently been confirmed by gene mapping, the PKU locus in man is determined to be on chromosome 12.

Animals↗

PubMed1983

Sequence homology between human alpha 1-antichymotrypsin, alpha 1-antitrypsin, and antithrombin III.

alpha 1-Antichymotrypsin mRNA was isolated by specific polysome immunoprecipitation from turpentine-treated baboon liver. The highly enriched mRNA was used for synthesis and cloning of the corresponding cDNA. Baboon alpha 1-antichymotrypsin cDNA clones were identified by hybrid-selected translation, and the insert DNA fragment from one of the putative clones was used as a probe to screen a human liver cDNA library comprised of 40 000 independent transformants. One of the human cDNA clones was unambiguously identified to contain alpha 1-antichymotrypsin DNA sequences by comparison of its 5'-terminal nucleotide sequence with the N-terminal amino acid sequence of the protein. This cDNA clone, designated phACT235, contains 1524 base pairs of human DNA, which was sequenced in its entirety. The inserted DNA codes for a 25 amino acid signal peptide sequence and the entire mature alpha 1-antichymotrypsin of 408 amino acid residues. Comparison of the amino acid sequence of alpha 1-antichymotrypsin with that of the human alpha 1-antitrypsin has revealed a homology level similar to that between chymotrypsin and trypsin.

Amino Acid Sequence↗

PubMed1983

Purification of antithrombin III mRNA and cloning of its cDNA.

Antithrombin III mRNA was enriched from a baboon liver by specific polysome immunoprecipitation. The partially purified antithrombin III mRNA preparation was used for cDNA synthesis and cloning. Candidate antithrombin III cDNA clones were identified by differential hybridization using as probes [32P]cDNAs synthesized from the polysome-enriched and -depleted RNA fractions, respectively. The candidate clones were further analyzed by hybrid-selected translation. The authenticity of a cDNA clone positive to both tests was unambiguously confirmed by matching its nucleotide sequence with the known amino acid sequence of human antithrombin III. The baboon antithrombin III cDNA clone hybridized well with human antithrombin III mRNA and can be used as a probe to isolate the corresponding human gene.

Animals↗

PubMed1983

Construction and identification of mouse amelogenin cDNA clones.

The determination of the biochemical phenotype of tooth epithelium requires specification by the dental mesenchyme. This is a general feature of epithelial-mesenchymal interaction in a number of different epidermal organ systems (e.g., salivary gland, mammary gland, feather, skin, and hair morphogenesis). To investigate these developmental processes, we have identified a cDNA clone representing the major group of gene products associated with enamel extracellular matrix formation. The mRNAs for mouse amelogenins, representing approximately equal to 90% of the total enamel proteins, have been isolated and partially characterized by specific immunoprecipitation. The poly(A)-containing RNAs were used for the synthesis and cloning of the mouse amelogenin cDNA. Recombinant plasmids containing amelogenin cDNA sequences were identified by differential hybridization, hybrid-selected translation, and blot hybridization analyses. A cloned sequence was used to identify the expression of amelogenins during tooth development. The mouse cDNA sequence hybridized to genomic mouse and human DNAs. This amelogenin cDNA probe now enables molecular investigations of a number of classical problems in developmental biology.

Amelogenin↗

PubMed1982

Polysome immunoprecipitation of phenylalanine hydroxylase mRNA from rat liver and cloning of its cDNA.

The mRNA for phenylalanine hydroxylase (phenylalanine 4-monooxygenase, EC 1.14.16.1) has been purified from total rat liver mRNAs, of which it constitutes less than 0.25%, to greater than 10% purity in a single step by specific polysome immunoprecipitation. The purified mRNA was used for synthesis and cloning of its cDNA. Recombinant colonies containing phenylalanine hydroxylase DNA sequences were identified by differential hybridization, hybrid-selected translation, and blot hybridization analysis. The rat cDNA clone was capable of hybridizing with human phenylalanine hydroxylase mRNA, which will permit the isolation of the corresponding human gene for analysis of phenylketonuria, a hereditary disorder in phenylalanine metabolism that causes permanent mental retardation in humans.

Animals↗

PubMed1980

Biochemical aspects of variation in foot-and-mouth disease virus.

The biochemical basis for variation in foot-and-mouth disease virus (FMDV) has been explored by analysis of the virus RNA and the virus-induced and structural proteins of three isolates of the virus. Two of the isolates were from serotype A and the third was from serotype O. Hybridization studies of the RNAs showed greater than 80% homology between the two type A viruses and about 65% homology between the two type A viruses and the virus of type O. The ribonuclease T1 maps of the three viruses gave distinct patterns typical of FMDV, but did not show that any two of the three viruses were more closely related. The virus-induced primary translation products, P88, P52 and P100 isolated from infected cells, were compared by tryptic peptide analysis. Combinations of 3H- and 14C-leucine-labelled polypeptides were hydrolysed with trypsin and resolved on an ion-exchange column. Much greater differences were found in P88 than in P52 or P100, indicating that the major variation occurs in the region of the genome coding for the structural proteins. Similar analysis of combinations of the structural proteins of the three viruses showed that there were differences in VP1, VP2 and VP3 and these results were supported by those obtained by PAGE analysis of the Staphylococcus aureus V8 protease cleavage products.

Aphthovirus↗

PubMed1979

Comparative biochemical and serological analysis of five isolates of a single serotype of foot-and-mouth disease virus.

A comparison has been made of some of the biochemical and serological characteristics of five isolates of foot-and-mouth disease virus (FMDV), serotype A. Three of the viruses have been assigned to the same subtype, A22; the other two belong to different subtypes, A5 and A24. RNA competition hybridization and two-dimensional electrophoresis of the oligonucleotides produced by ribonuclease T1 showed that the three A22 viruses formed a group which could be distinguished from the A5 and A24 viruses. However, the three A22 viruses showed some differences by both tests. Analysis of the virus polypeptides by polyacrylamide gel electrophoresis methods also distinguished the A22 viruses as a group distinct from the A5 and A24 viruses, but small differences within the A22 group were observed using electrofocusing techniques. Serological differences were observed between the viruses using complement fixation tests and by competition radioimmunoassay with antisera obtained from guinea pigs infected with these viruses. The greatest similarity occurred between the viruses previously subtyped as A22, with A5 and A24 being distinct from the A22 group and from each other. The relationship of the biochemical and serological data is discussed.

Animals↗

PubMed1977

An assessment by competition hybridization of the sequence homology between the RNAs of the seven serotypes of FMDV.

A comparison has been made of the RNAs of the seven serotypes of foot-and-mouth disease virus (FMDV) by competition hybridization. Homology among the three European serotypes A, O, C and the Asia I serotype was 60 to 70%. Similar homologies were found among the three Southern African Territories serotypes (SAT I, SAT 2, SAT 3), but homology between the two groups was much lower (25 to 40%). Homology between the RNAs of subtypes within serotypes A and O was greater than 70%. Double competition experiments with the Eropean serotypes indicate sharing of nucleotide sequences.

Aphthovirus↗

PubMedDate not supplied

Cloned human phenylalanine hydroxylase gene allows prenatal diagnosis and carrier detection of classical phenylketonuria.

The human gene for the hepatic enzyme phenylalanine hydroxylase has been cloned and used to analyse the phenylalanine hydroxylase locus in the human genome. The detection of polymorphisms in this locus by several restriction enzymes has allowed feasibility studies of prenatal diagnosis of classical phenylketonuria and identification of carriers of the trait. Results indicate that these services could be provided for up to 75% of all families with phenylketonuric children in the general Caucasian population.

Alleles↗