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Biomedical subjects

W F Anderson

Publications and source records attributed to W F Anderson.

At least 289 records · Page 16Linked to original sources
PubMed1982

Erythropoietin-independent erythroid colony formation in patients with erythroleukaemia (M6) and related disorders.

In vitro erythropoietin (Ep) responsiveness of human bone marrow mononuclear cells was determined in 12 normal human volunteers and four patients with erythroleukemia (EL), two patients with refractory anaemia with excess blasts (RAEB), and one patient with de novo acute myelogenous leukaemia (AML). The bone marrow cells were cultured in a microtitre methylcellulose system containing 30% human AB serum and human urinary Ep in concentrations ranging from 0 to 2 units/ml. Erythroid colony growth from normal marrow cultures was Ep-dependent. It was augmented by added Ep and inhibited by Ep antiserum. Marrow cells from one patient with EL and one patient with RAEB after transformation to AML had no erythroid colony formation with or without added Ep. All of the remaining patients formed 'spontaneous' or endogenous erythroid colonies (EEC) without the addition of Ep. In three of these (two with EL and one with de novo AML), the erythroid colony formation was augmented by added Ep. In three other patients (one with EL and two with RAEB), erythroid colony growth was unaffected by added Ep or Ep antiserum, and thus appeared to be Ep-independent.

Aged↗
PubMed1981

Gene therapy.

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Cloning, Molecular↗
PubMed1981

Recovery of recombinant bacterial plasmids from E. coli transformed with DNA from microinjected mouse cells.

We have previously described the isolation of thymidine kinase positive (TK+), human beta-globin gene-containing colonies following co-microinjection of mouse TK- L cells with two recombinant pBR322 plasmids, one containing the TK gene of herpes simplex virus type I (plasmid pXl), and the second containing a human genomic DNA fragment within which is the human beta-globin gene (plasmid pRKl). DNA isolated from one such clone was used in bacterial transformation experiments with a selection for tetracycline-resistant colonies (that is, for cells containing pRKl). A total of forty-two tetracycline-resistant colonies were isolated, thirty of which contained circular pRK1 molecules identical to those originally injected. The remaining twelve colonies contained unique plasmids that were grouped into five different classes of recombinant molecules. All five of these unique recombinant classes appear to contain a common deletion endpoint occurring at a specific region of the pBR322 segment of pRKl. Four of the unique recombinant classes appear to have arisen from the deletion of a segment of a pRKl trimer or dimer molecule, while the fifth class appears to have resulted from recombination between pRKl and pXl followed by a deletion event within this recombinant. It is uncertain whether these deletions are occurring within the eukaryotic cell or upon subsequent transformation of the bacterial cell. If the latter, then the passage of the plasmid DNA through the eukaryotic cell alters a specific site of the pBR322 DNA in such a way that deletions can occur at a high frequency in this region when the plasmid DNA is introduced back into a bacterial cell. Thus, we have established a prokaryote-eukaryote-prokaryote DNA transfer and recovery system which should be useful in studies on DNA replication and the regulation of gene expression in higher eukaryotes.

Animals↗
PubMed1981

Structure of the cro repressor from bacteriophage lambda and its interaction with DNA.

The three-dimensional structure of the 66-amino acid cro repressor protein of bacteriophage lambda suggests how it binds to its operator DNA. We propose that a dimer of cro protein is bound to the B-form of DNA with the 2-fold axis of the dimer coincident with the 2-fold axis of DNA. A pair of 2-fold-related alpha-helices of the repressor, lying within successive major grooves of the DNA, seem to be a major determinant in recognition and binding. In addition, the C-terminal residues of the protein, some of which are disordered in the absence of DNA, appear to contribute to the binding.

Bacteriophage lambda↗
PubMed1981

Common precursor of lysozymes of hen egg-white and bacteriophage T4.

The lysozymes of hen egg-white and bacteriophage T4 have similar catalytic properties but their amino acid sequences are not homologous. The question therefore arises whether they are derived from a common ancestral protein or have arisen independently. On the basis of the data we have gathered, it is shown here that the two enzymes are similar in the conformation of their backbones, in their modes of binding substrates, in specific protein--substrate interactions and in their presumed modes of action. We conclude that the two enzymes have diverged from a common precursor. This seems to be the most convincing example to date of the divergence of proteins with nonhomologous amino acid sequences.

Animals↗
PubMed1981

Mouse alpha-globin genes and alpha-globin-like pseudogenes are not syntenic.

A genetic polymorphism for a Bgl I endonuclease site near the alpha-globin-like pseudogene alpha-4 of C57BL/6 and C3H/HeN mice was used to show that alpha-4 was not affected by three independent mutations in which the adult globin genes alpha-1 and alpha-2 were deleted. These results indicated that alpha-4 might not be located adjacent to the adult alpha-globin genes on chromosome 11. Restriction endonuclease analysis of DNA of a primary clone of a Chinese hamster--mouse somatic cell hybrid that had lost mouse chromosomes 11 and 18 showed that this clone lacked the adult murine globin genes alpha-1 and alpha-2 but it did contain the alpha-globin-like pseudogenes alpha-3 and alpha-4. These results indicated that the adult alpha-globin genes and alpha-globin-like pseudogenes are not located on the same chromosome. Similar analyses of several other Chinese hamster--mouse somatic cell hybrids that had segregated other mouse chromosomes indicated that the alpha-globin-like pseudogenes alpha-3 and alpha-4 are located on mouse chromosomes 15 and 17, respectively. These data explain why alpha-3 and alpha-4 were not affected by the three independently induced deletion-type mutations that cause alpha-thalassemia in the mouse.

Animals↗
PubMed1981

Deletions in the alpha-globin gene complex in alpha-thalassemic mice.

Three induced, heritable mutations in the mouse cause alpha-thalassemias. The adult alpha-globin genes on each mutant chromosome are no longer expressed. Embryos heterozygous for one normal and any of the three mutant chromosomes also seem to be deficient in embryonic alpha-globin-like x-globin, suggesting that the x-globin gene is nearby and also inactivated. A normal genetic polymorphism for a specific EcoRI site in or around the mouse alpha-globin gene complex has been used here to show that each of the three mutated chromosomes has a deletion that includes the segment of a 12-kilobase EcoRI band which normally carries one of the two adult alpha-globin genes. The deletion of the comparable part of the second alpha-globin gene site is also inferred. Nonetheless, a 4.7-kilobase EcoRI segment which carries a characterized alpha-globin-like pseudogene is still present in each mutant. These mutations were recovered after triethylenemelamine or x-ray treatments.

Animals↗
PubMed1981

Three mouse models of human thalassemia.

Three types of mice with globin gene mutations, called 352HB, 27HB, and Hbath-J, appear to be true animal models of human thalassemia. Expression of the alpha-globin genes in three stocks of mice, each one heterozygous for one of the alpha-globin mutations, was examined at the polypeptide, RNA, and DNA levels. alpha-Globin polypeptide chains, relative to beta-globin chains in heterozygous thalassemic mice, are present at approximately 80% of normal. The ratios of alpha-globin to beta-globin RNA sequences are also 75-80% of normal, exactly reflecting the alpha-globin to beta-globin chain ratios. In the case of mutant 352HB, at least one alpha-globin gene is deleted. Thalassemic mouse erythroid cells appear to compensate partially for the loss of half of their alpha-globin genes.

Animals↗
PubMed1981

Regional gene assignment of human porphobilinogen deaminase and esterase A4 to chromosome 11q23 leads to 11qter.

The regional gene assignments for human porphobilinogen deaminase (PBGD; EC 4.3.1.8) and esterase A4 (ESA4; EC3.1.1.1) chromosome 11 have been determined with somatic cell hybridization and immunologic, electrophoretic, and cytogenetic techniques. Dimethyl sulfoxide-induced erythroid differentiation of hybrid clones derived from the fusion of tetraploid Friend murine erythroleukemia (2S MEL) cells deficient in thymidine kinase and human Lesch--Nyhan fibroblasts (HLN) deficient in hypoxanthine phosphoribosyltransferase (HPRT-; EC 2.4.2.8) were examined for expression of human PBGD, ESA4, and lactate dehydrogenase A (LDHA; EC 1.1.1.27). Human PBGD was detected by rocket immunoelectrophoresis with rabbit anti-human PBGD IgG and by isoelectric focusing. The human chromosome complement of each clone was determined by cytogenetic and enzyme marker analyses. Of the five primary 2S MEL--HLN clones examined, three were positive for human PBGD. These were subcloned to yield a total of 10 secondary, tertiary, or quaternary clones. Analyses of these subclones permitted the regional assignment of human PBGD and ESA4 to the long arm of chromosome 11. Finer regional assignment of the loci for human PBGD and ESA4 was facilitated when two 2S MEL (HPRT-)--human fibroblast (HX/11) hybrids, each containing the X chromosome--autosome translocation (der11), t(X;11)(q25-26;q23) as the only human chromosome, were examined for expression of human PBGD, ESA4, and LDHA. One clone, HX/11-2, contained the intact X/11 translocated chromosome; in the other, HX/11-3, 11p was deleted, and the human X/11 derivative was translocated onto a mouse chromosome. HX/11-2 expressed human LDHA, but HX/11-3 did not, verifying that the latter human 11/X derivative did not include 11pter leads to 11p12; PBGD and ESA4 were not detected in either hybrid. These results confirm the location of the gene for human PBGD on chromosome 11 and establish the assignment of the loci for PBGD and ESA4 in the region 11q23 leads to 11qter.

Ammonia-Lyases↗
PubMed1980

The beta-globin gene is on the short arm of human chromosome 11.

Investigations on the regulation of human globin gene expression are assisted by a knowledge of the chromosomal location of the globin genes. Previous studies have mapped the alpha-globin locus to human chromosome (HC) 16, and have shown that the human globin gene complex gamma-delta-beta co-segregates with lactate dehydrogenase A (LDH-A) and the presence of HC 11 in somatic cell hybrids. Radioactively labelled globin complementary DNA (cDNA) probes were used in molecular hybridisation experiments to determine the chromosomal locations of the alpha- and beta-globin genes. When human x rodent somatic cell hybrids are used which contain well-defined parts of human chromosomes, direct mapping of genes of chromosomal regions or single bands is possible. We have regionally localised the human beta-globin gene using two sets of hybrid cell lines: (1) Chinese hamster x human hybrid cells containing the HC 11 long arm or both the short and long arms and (2) mouse x human hybrids containing only the HC 11 short arm. The techniques of liquid molecular hybridisation and Southern blotting with 32P-labelled human beta-globin cDNA (from plasmid JW102) have been used to localise the beta-globin gene sequence to region 11p11 leads to 11p15. Similar results were reported recently by Jeffreys et al.

Chromosomes, Human, 6-12 and X↗