Cloning and chromosomal localization of a human endothelin ETA receptor.

A cDNA clone encoding a human endothelin receptor was isolated from a placenta cDNA library. The deduced amino acid sequence of the clone is 94% identical to the bovine endothelin ETA receptor and represents the human homologue. The human endothelin ETA receptor gene was localized to chromosome 4 by analysis of its segregation pattern in rodent-human hybrids.     

An Intermediate Pluripotent State Controlled by MicroRNAs Is Required for the Naive-to-Primed Stem Cell Transition

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Analysis of copia sequence variation within and between Drosophila species

The sequences of the 5' long-terminal repeat (LTR) and adjacent leader regions of 27 full-length copia elements isolated from natural populations of Drosophila melanogaster, D. simulans, and D. mauritiana are presented. Phylogenetic analyses indicate that although D. melanogaster copia elements are distinct from those of D. simulans and D. mauritiana, the elements of these latter two species are not distinguishable from one another. LTRs and adjacent 5' leader regions of elements isolated from D. simulans and D. mauritiana are structurally similar to one another and carry substantial deletional variation mapping to regions previously identified as being of potential importance for copia expression.      

Affinity Selection and Mass Spectrometry-Based Strategies to Identify Lead Compounds in Combinatorial Libraries

The screening of diverse libraries of small molecules created by combinatorial synthetic methods is a recent development which has the potential to accelerate the identification of lead compounds in drug discovery. We have developed a direct and rapid method to identify lead compounds in libraries involving affinity selection and mass spectrometry. In our strategy, the receptor or target molecule of interest is used to isolate the active components from the library physically, followed by direct structural identification of the active compounds bound to the target molecule by mass spectrometry. In a drug design strategy, structurally diverse libraries can be used for the initial identification of lead compounds. Once lead compounds have been identified, libraries containing compounds chemically similar to the lead compound can be generated and used to optimize the binding characteristics. These strategies have also been adopted for more detailed studies of protein–ligand interactions.     

The human VAV proto-oncogene maps to chromosome region 19p12→19p13.2

Summary A novel human oncogene, designated VAV, has been recently characterized. This oncogene was generated by a rearrangement within the 5 coding sequences of a normal cellular gene, the VAV proto-oncogene. The normal VAV gene is specifically expressed in hematopoietic cells regardless of their differentiation lineage. We now report that the VAV locus has been localized in the human genome at chromosome 19p12 19p13.2 by analysis of its segregation pattern in rodenthuman somatic cell hybrids and by chromosomal in situ hybridization. The VAV locus might be closely linked to the insulin receptor (INSR) locus, as suggested by comigration of INSR and VAV high-molecular-weight DNA fragments after pulsed-field gel electrophoresis. The VAV chromosomal assignment is of interest because chromosome region 19p13 is involved in different karyotypic abnormalities in a variety of malignancies including melanomas and leukemias. The identification of a novel proto-oncogene that maps to that region will enable us to define whether VAV is involved in any of the translocations observed.     

Assignment of the erythropoietin receptor (EPOR) gene to mouse chromosome 9 and human chromosome 19

Erythropoietin (EPO), the primary regulator of mammalian erythropoiesis, binds and activates a specific receptor on erythroid progenitors. The human and mouse cDNAs for this receptor (EPOR) have recently been isolated. These cDNAs were used to establish the genomic location of the EPOR gene. By somatic cell hybrid analysis, the locus for the EPOR maps to human chromosome (Chr) 19pter-q12. By interspecific backcross mapping the locus is tightly linked to the murine Ldlr locus near the centromere of mouse Chr9. This region of mouse Chr9 is homologous to a region of human Chr 19p13 carrying the human LDLR and MEL loci, strongly suggesting that the human EPOR gene is at 19p13 near the human LDLR locus.     

Structural and functional dynamics of oogenesis in Glossina austeni: general features, previtellogenesis and nurse cells.

Glossina austeni oogenesis throughout its nine-day pregnancy cycle is described with the focus on previtellogenic stages. The ultrastructural details of the oocyte-nurse cell relationship and cyst formation is presented. The oocyte develops in a syncytial association with 15 nurse cells with the entire unit surrounded by a follicular epithelium. The nurse cells have large elaborate nucleoli. Evidence of nuclear emissions and the presence of an unusual cytoplasmic membrane association were found. A variety of nuclear inclusions are seen in the oocyte. Glycogen, lipid, ribosomes and membrane organelles accumulate in the oocyte during previtellogenesis.     

The co-carcinogenic activity of 4-nitropyridine-1-oxide (4-npo) and prevention of transformation by type-specific anti-viral antibodies

Summary Fischer rat embryo cells chronically infected with Rauscher murine leukemia virus, and known to be sensitive to transformation by potent chemical carcinogens, were transformed by the weak carcinogen 4-nitropyridine-1-oxide. Transformed cells grew in semi-solid agar and produced tumors in newborn Fischer rats. Transformation was inhibited by antisera specific for the ecotropic Rauscher murine leukemia virus, but not by antisera of equal toxicity specific for xenotropic Swiss mouse AT-124 virus. This work was supported by contract NO1-CP-43240 within the Virus Cancer Program of the National Cancer Institute.