Mutations in the murine fitness 1 gene result in defective hematopoiesis.

Identification and characterization of mutations that disrupt normal hematopoiesis are essential for understanding the genetic pathways that control the development and regulation of the mammalian hematopoietic system. Previously, the fitness 1 gene was identified by five, independent mutations in N-ethyl-N-nitrosourea (ENU) saturation mutagenesis experiments within the albino (c) region of mouse chromosome 7 (MMU7). We report here that fit1 mutants are anemic, display numerous peripheral blood defects, and are deficient in early hematopoietic progenitor cell populations.

Inherited somatic mosaicism caused by an intracisternal A particle insertion in the mouse tyrosinase gene.

A recessive, fully penetrant mutation (c(m1OR)) at the mouse albino locus that results in coat-color mottling has been characterized at the molecular level. Restriction mapping and DNA sequencing analyses provide evidence that mutants carry a 5.4-kb intracisternal A particle (IAP) element insertion upstream of the tyrosinase (Tyr) promoter.

An oligopeptide transport gene from Candida albicans.

A Candida albicans oligopeptide transport gene, OPT1, was cloned from a C. albicans genomic library through heterologous expression in the Saccharomyces cerevisiae di-/tripeptide transport mutant PB1X-9B. When transformed with a plasmid harbouring OPT1, S.

Phenotypic consequences of deletion of the gamma 3, alpha 5, or beta 3 subunit of the type A gamma-aminobutyric acid receptor in mice.

Three genes (Gabrg3, Gabra5, and Gabrb3) encoding the gamma 3, alpha 5, and beta 3 subunits of the type A gamma-aminobutyric acid receptor, respectively, are known to map near the pink-eyed dilution (p) locus in mouse chromosome 7. This region shares homology with a segment of human chromosome 15 that is implicated in Angelman syndrome, an inherited neurobehavioral disorder. By mapping Gabrg3 on a panel of p-locus deletions, we have determined that the order of genes within this cluster is centromere-p(D15S12h)-Gabrg3-Gabra5-Gabrb3-telom ere.

Balbiani ring hnRNP substructure visualized by selective staining and electron spectroscopic imaging.

The Balbiani Rings (BR) in the polytene chromosomes of Chironomus salivary glands are intense sites of transcription. The nascent RNPs fold during transcription into 40-50-nm granules, containing in the mature transcript approximately 37-kb RNA. Using a new nucleic acid specific stain, osmium ammine B on Lowicryl sections, in combination with electron energy filtered imaging of sections containing BR granules, we demonstrate a RNA-rich particulate substructure (10-nm particle diameter; 10-12 particles per BR granule).

Female-specific mutagenic response of mice to hycanthone.

Male and female gametogeneses differ markedly in all mammals. While male germ cells are continuously being produced from stem cells throughout the reproductive life span, the number of female germ cells is fixed during prenatal development and, soon after birth, all of the oocytes are arrested in a modified diplotene, or dictyate, stage. Following puberty, dictyate oocytes are hormonally triggered to mature either singly or in groups, resulting in ovulation and the completion of the first meiotic division.

Biochemical properties of site-directed mutants of human epidermal growth factor: importance of solvent-exposed hydrophobic residues of the amino-terminal domain in receptor binding.

Eight analogues of human epidermal growth factor (hEGF) having specific amino acid substitutions in the beta-sheet structure (residues 19-31) of the amino-terminal domain were generated by site-directed mutagenesis. Affinity of the epidermal growth factor (EGF) receptor for each of these mutant hEGF analogues was measured by both radioreceptor competition binding and receptor tyrosine kinase stimulation assays. The relative binding affinities obtained by these two methods were generally in agreement for each hEGF species.

The aggregation states of spinach phosphoribulokinase.

Phosphoribulokinase (PRK; EC 2.1.7.

Structure of the nucleosome core particle at 8 A resolution.

The x-ray crystallographic structure of the nucleosome core particle has been determined using 8 A resolution diffraction data. The particle has a mean diameter of 106 A and a maximum thickness of 65 A in the superhelical axis direction. The longest chord through the histone core measures 85 A and is in a non-axial direction.

A domain that assumes a Z-conformation includes a specific deletion in some cloned variants of a complex satellite.

Sequence analyses show that deletions of 10 and 12 bp occur at homologous sites in a domain that is rich in alternating purines and pyrimidines (Pu/Py) in B42 and EXT, two cloned variants of a complex satellite DNA. A 3-bp deletion occurs 27 bp upstream from the site of the specific deletions in B42 and RU, a third cloned satellite variant that has not suffered the 10-bp deletion. Under torsional stress, the Pu/Py-rich domain adopts a Z-conformation as shown by (i) inhibition of cutting at a BssHII site that accounts for 2/5 of a 15-bp tract of pure Pu/Py in the domain; (ii) binding of polyclonal and monoclonal anti-Z-DNA antibodies to the domain; and (iii) antibody stabilization and subsequent relaxation of the Z-region.

Cadmium resistance in Drosophila: a small cadmium binding substance.

A small cadmium-binding substance (CdBS) has been observed in adult Drosophila melanogaster that were raised for their entire growth cycle on a diet that contained 0.15 mM CdCl2. Induction of CdBS was observed in strains that differed widely in their sensitivity to CdCl2.

Distance between two active-site lysines of ribulose bisphosphate carboxylase from Rhodospirillum rubrum.

In the absence of a three-dimensional structure of ribulose-bisphosphate carboxylase/oxygenase [3-phospho-D-glycerate carboxy-lyase(dimerizing), EC 4.1.1.

Prostaglandin modulation of phorbol ester skin tumor promotion.

TPA promotion of skin tumors in mice can be modified by application of various prostaglandins or their precursors. The effects depend on the particular prostaglandin used: PGF2alpha enhances promotion, whereas PGE1 consistently inhibits promotion. Time of application of the prostaglandin with respect to TPA determines whether PGE2 enhances or inhibits.

Rapid release of protease inhibitors from soybeans: immunochemical quantitation and parallels with lectins.

Specific antisera were prepared against the Bowman-Birk trypsin inhibitor and four other trypsin inhibitors of low molecular weight isolated from soybeans (Glycine max L. cv. Tracy).

Osmotic shrinkage as a factor in freezing injury in plant tissue cultures.

Haplopappus gracilis and Acer saccharum tissue culture cells are extremely sensitive to freezing injury, and exhibit a decrease in survival from 98% at -1 C to 4% at -3 C (Haplopappus) and 92% at -3 C to 13% at -5 C (Acer) when suspended in distilled H(2)O, seeded at -1 C, and then cooled by 0.1 C/minute. Similar results are obtained when cells are suspended in growth medium.

Light-stimulated Production of a Chloroplast-localized System for Protein Synthesis in Euglena gracilis.

Chloroplasts and proplastids isolated respectively from autotrophic and dark-adapted cells of Euglena gracilis strain Z incorporated (14)C-l-leucine into protein. In each case the incorporation was inhibited by chloramphenicol (50% inhibition at about 5 mug/ml for chloroplasts and 30 mug/ml for proplastids), but not appreciably by cycloheximide at concentrations up to 200 mug/ml. Chloroplasts from autotrophic cells incorporated leucine into protein at rates of about 10 pg leucine per mg RNA in one minute, but isolated proplastids were only 5 to 10% as active.

Protein synthesis by isolated etioplasts and chloroplasts from pea and wheat and the effects of chloramphenicol and cycloheximide.

Etioplasts capable of incorporating (14)C-leucine into protein have been isolated from dark-grown pea and wheat plants. The requirements for leucine incorporation for etioplasts were similar to those for chloroplasts. An ATP-generating system, Mg(2+), and GTP were required.