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S Goff

Publications and source records attributed to S Goff.

33 records · Page 2Linked to original sources
PubMed1987

Human beta-globin gene expression after gene transfer using retroviral vectors.

A retroviral vector containing a 4.4-kb Pst I human beta S-globin gene and a neomycin resistance gene was used to infect NIH-3T3 and mouse erythroleukemia cells (MELC). In MELC, human beta-globin mRNA transcripts are transcribed and properly initiated and spliced. In some cases, there is an appropriate increase in beta-globin mRNA on addition of dimethylsulfoxide (DMSO), an inducer of hemoglobin synthesis and erythroid differentiation in these cells. When NIH-3T3 cells are infected with the same retroviral vector, there is less globin mRNA accumulation and no evidence for appropriate regulation. Human beta-globin gene expression in MELC clones induced with DMSO is 2-3% that of endogenous mouse beta-globin gene expression. These results indicate that retroviral vectors can be used to transfer and appropriately express human beta-globin genes in erythroid cells.

Cells, Cultured↗
PubMed1984

The mouse c-abl locus: molecular cloning and characterization.

The mouse c-abl gene, part of the sequence of which was captured in Moloney murine leukemia virus to generate the transforming gene (v-abl) of the Abelson murine leukemia virus, has been isolated and characterized. The c-abl locus spans 40 kb in the mouse genome with the v-abl homologies distributed in no less than ten clusters along 25 kb of the cloned DNA. Partial sequence of the v-abl homologous regions indicates that v-abl derived from c-abl mainly by splicing of multiple exons of the c-abl gene. The c-abl sequences can be subdivided into two regions: a tyrosine kinase coding sequence distributed among eight small clusters on the 5' end of the gene and a C-terminal portion consisting of one small and one large cluster, which are needed neither for the tyrosine kinase activity nor for the transforming ability of v-abl. Apparent exon/intron boundaries in the homologous kinase-coding regions of c-abl and c-src are at different locations.

Amino Acid Sequence↗
PubMed1981

Isolation and properties of Moloney murine leukemia virus mutants: use of a rapid assay for release of virion reverse transcriptase.

A rapid assay for retroviral reverse transcriptase activity released into the culture medium by infected cells was developed. With the assay, 4,000 clonally infected cell lines could be tested in a few hours. We have adapted the assay for use as a screen for the detection of spontaneous viral mutants. Mutants of Moloney murine leukemia virus have been isolated which (i) produce a thermolabile reverse transcriptase, (ii) are temperature sensitive for release of enzyme activity, or (iii) can only productively infect cells already producing gag-related polypeptides. The assay has also been useful for the isolation of nonproducer cells infected with various replication-defective transforming viruses.

Culture Media↗
PubMed1980

Structure of a cloned circular Moloney murine leukemia virus DNA molecule containing an inverted segment: implications for retrovirus integration.

Closed circular Moloney murine leukemia virus (M-MuLV) DNA was prepared from recently infected cells and cloned in a lambda vector. Four classes of cloned M-MuLV inserts were found: Class I, full length 8.8-kilobase (kb) inserts with two tandem long terminal repeats (LTRs) of 600 base pairs; class 2, 8.2-kb inserts with a single copy of a LTR; class 3, M-MuLV DNA inserts with various portions deleted; and class 4, an 8.8-kb insert with an internal sequence inversion. Determination of nucleotide sequence at the junction between the two LTRs from a class 1 insert suggested that circularization occurred by blunt-end ligation of an 8.8-kb linear DNA. The class 4 molecule had an inversion that was flanked by inverted LTRs, each of which had lost two terminal base pairs at the inversion end points. Also, four base pairs that were present only once in standard M-MuLV DNA were duplicated at either end of the inversion. This molecule was interpreted as resulting from an integrative inversion in which M-MuLV DNA has integrated into itself. Its analysis thus provided explicit information concerning the mechanism by which retrovirus DNA integrates into host cell DNA. Models of retrovirus integration based on bacterial DNA transposition mechanisms are proposed.

Bacteriophage lambda↗
PubMed1980

A transformation-defective mutant of Abelson murine leukemia virus lacks protein kinase activity.

A transformation-defective mutant of Abelson murine leukemia virus (A-MuLV), called A-MuLV-P92td, has been isolated. The mutant encodes a serologically identifiable A-MuLV protein of molecular weight 92,000 (P92) but it lacks the ability to transform either fibroblasts or bone marrow lymphoid cells. In contrast to the protein made by transforming strains of A-MuLV, the protein made by A-MuLV-P92td does not becme phosphorylated during in vitro incubation with [gamma-32P]ATP. If the protein is mixed with proteins from cells transformed by a functional A-MuLV strain, phosphorylation of P92 occurs, showing that its ability to accept phosphate is not altered by the mutation. These parallel changes provide genetic evidence that the A-MuLV protein is a transforming protein and that its associated protein kinase activity (EC 2.7.1.37) is a crucial part of its transforming ability.

Abelson murine leukemia virus↗
PubMed1979

In vitro synthesis of a 9 kbp terminally redundant DNA carrying the infectivity of Moloney murine leukemia virus.

Detergent-disrupted virions of Moloney murine leukemia virus synthesize a 9 kbp double-stranded infectious DNA. It contains mainly full-length, single-stranded DNA, and its infectivity and size are insensitive to digestion by the single-strand-specific S1 nuclease. Analysis of fragmentation of the DNA using restriction endonucleases has shown that it is indistinguishable from the linear double-stranded DNA synthesized in infected cells. On the basis of the positions of the cleavage sites for a number of enzymes, the 9 kbp DNA has a 575 base direct terminal repetition. It is longer than the viral RNA at both ends, evidently due to repetitive copying of segments of the RNA. Virions also synthesize an 8.4 kbp double-stranded circular DNA that lacks one copy of the terminal repetition, as well as viral DNA longer than 9 kbp. The enzymatic machinery in the virions of retroviruses therefore appears to be responsible for all the steps involved in making fully double-stranded linear and one form of circular DNA.

Base Sequence↗
PubMed1979

Structure of the Abelson murine leukemia virus genome.

Virions produced from cells transformed by A-MuLV contain a 30S, 5.6 kb RNA that can be translated in a cell-free system to form the characteristic A-MuLV protein. This RNA was mapped by heteroduplex methods using DNA probes from M-MuLV, the presumed parent of A-MuLV. The overall organization of the RNA was determined by using full-length M-MuLV reverse transcribed DNA and visualizing the heteroduplexes in the electron microscope. This showed that A-MuLV and M-MuLV have homologous sequences at both ends of their RNAs but that the central portion of the A-MuLV genome is not homologous to sequences in M-MuLV RNA. A precise measure of the lengths of the shared regions was obtained by using S1 nuclease to digest hybrids between 32P-labeled M-MuLV DNA and A-MuLV RNA; the resulting fragments were analyzed for their length by electrophoresis. The regions of homology were shown to be 1320 nucleotides long at the 5' end and 730 nucleotides long at the 3' end. Thus approximately 6200 nucleotides of the approximately 8300 in M-MuLV RNA were deleted when the A-MuLV genome was formed, but an insert of 3600 nucleotides, presumably derived from the normal murine genome, was inserted in place of the deleted region.

Abelson murine leukemia virus↗
PubMed1979

A detailed model of reverse transcription and tests of crucial aspects.

A model of reverse transcription has been devised by which the detailed architecture of ten molecular structures is predicted. The model includes a number of novel features for which experimental evidence is presented. First, growing minus DNA strand is copied from the viral RNA only up to a position about 150 nucleotides from the 5' end of the RNA. Second, plus-strand DNA, after being copied from approximately 600 nucleotides at the 5' end of the minus-strand DNA, then transcribes the first approximately 20 nucleotides of the tRNApro primer (which is covalently attaced to the 5' end of the minus DNA strand). The 3' ends of the minus and plus DNA probably form a hybrid through the homology conferred by the primer binding site sequences. Third, the minus and plus DNA strands are elongated in a continuous fashion resulting in a linear double-stranded DNA molecule containing a 600 nucleotide direct repeat at both ends. The most of the features of the model have experimental support, and it appears to provide a credible description of reverse transcription.

DNA, Viral↗
PubMed1979

Synthesis of a 600-nucleotide-long plus-strand DNA by virions of Moloney murine leukemia virus.

A discrete, 600-nucleotide-long plus-strand DNA has been identified among the products of reverse transcription by virions of Moloney murine leukemia virus. Its polarity was shown by hybridization to minus-strand DNA. It appears to be copied from the right end of minus-strand DNA because (i) its restriction endonuclease cleavage pattern corresponds to the redundant 600-base segment found at either end of the ultimate double-stranded reverse transcription products, (ii) its synthesis is actinomycin D sensitive, and (iii) its synthesis begins during the first hour of a reverse transcription reaction when only the right-hand end of minus-strand DNA is available as template. We therefore call this DNA plus-strong-stop DNA by analogy with the minus-strong-stop DNA copied from the left end of the viral RNA. Both strong-stop DNAs are made early during in vitro reactions and decline in concentration later, consistent with postulated roles as initiators of long minus- and plus-strand DNA. Unlike minus-strong-stop DNA, plus-strong-stop DNA remains as a double-stranded nucleic acid after its synthesis, as shown by S1 nuclease resistance. A primer to initiate plus-strong-stop DNA synthesis has not been identified; the product found thus far has no detectable RNA attached to it.

Chromosome Mapping↗
PubMedDate not supplied

Epiploic appendicitis: CT characteristics.

Acute infarction of an appendix epiploica resulted in an inflammatory process involving the caudal aspect of the transverse colon and the adjacent greater omentum. Computed tomography demonstrated prominent linear soft tissue densities, an increase in CT number of the involved greater omentum, and posterior displacement of the small bowel. In the setting of acute abdominal pain the location and focal nature of the inflammatory process as seen on CT may allow the radiologist to suggest the correct diagnosis.

Colitis↗