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Biomedical subjects

H Hanafusa

Publications and source records attributed to H Hanafusa.

269 records · Page 15Linked to original sources
PubMed1971

DNA in uninfected and virus-infected cells complementary to avian tumor virus RNA.

The 70S RNA component of several avian tumor viruses was hybridized with DNA extracted from avian tumor virus-infected and uninfected chicken and Japanese quail cells. Tritium-labeled 70S RNAs from Rous sarcoma virus (RSV), Rous associated virus-1 (RAV-1), RAV-60, and Schmidt-Ruppin-RSV (SR-RSV) hybridize from 3 to 10 times more with DNA from uninfected chicken cells than with DNA from Escherichia coli, calfthymus, or baby hamster kidney cells. After infection of chicken cells with RSV(RAV-1), SR-RSV, or RAV-2, the amount of 70S avian tumor virus [(3)H]RNA hybridized increases by 1.6 times. The specificity of the hybridization reaction was shown by the specific competition of 70S SR-RSV [(3)H]RNA with 70S RNA from RSV(RAV-1), and not with RNA from Sendai virus or chicken cells. There was no difference in the hybridization of 70S RNA from RSV (RAV-1), RAV-1, or RAV-60 with DNA either from chicken cells that contain RAV-60 in a nonreplicating form or from chicken cells that do not appear to contain RAV-60. These results indicate that both types of uninfected chicken cells contain DNA that is complementary to RNA from several avian tumor viruses and that the amount of complementary DNA increases in such cells after infection with an avian tumor virus. The RNAs of genetically different avian tumor viruses appear to have indistinguishable base sequences by this technique.

Alpharetrovirus↗
PubMed1970

A cell-associated factor essential for formation of an infectious form of Rous sarcoma virus.

Formation of a specific type of infectious Rous sarcoma virus called RSV(0) has been found to occur only in a certain type of chick embryo cell in the absence of avian leukosis virus. Although these chick cells lack any complete form of avian leukovirus, they appear to carry a genetic factor essential for formation of infectious RSV(0). A factor-deficient cell can be converted to a producer of infectious RSV(0) by infection with Rous sarcoma virus or avian leukosis virus which has been grown in factor-containing cells. Evidence is presented to show that the factor determines both the antigenic and host range specificity of RSV(0).

Animals↗
PubMed1970

Recovery of a new virus from apparently normal chick cells by infection with avian tumor viruses.

Cells derived from the majority of chick embryos, although free of presently known avian tumor virus particles, appear to contain genetic materials similar to those found in this virus group. After infection of these cells with avian leukosis or Rous sarcoma virus, the genetic factor was recovered by incorporation into mature infectious virus. The newly isolated virus (RAV-60) did not require the assistance of another virus for its replication. The virus had most of the attributes of an RNA-containing avian leukosis virus, and its outer structure resembled the Rous sarcoma virus known as RSV(0).

Alpharetrovirus↗
PubMed1969

Rapid transformation of cells by Rous sarcoma virus.

The conditions for synchronous transformation of chick embryo cells by infection with Rous sarcoma virus are studied. Two factors, the treatment of cells with DEAE-dextran and the use of cells which grow rapidly following virus infection, are found to be most important. Under the conditions described, the Schmidt-Ruppin strain of Rous sarcoma virus at a multiplicity of higher than 5 induces morphological alteration in about 90 per cent of the cell population within 24 hours after infection. The alteration in the morphology is accompanied by acquisition of the ability of cells to grow in agar medium and by the increased rate of incorporation of thymidine and uridine into nucleic acids.

Animals↗
PubMedDate not supplied

An N-terminal peptide from p60src can direct myristylation and plasma membrane localization when fused to heterologous proteins.

The src gene product, p60src, of Rous sarcoma virus (RSV) is a tyrosine-specific protein kinase which is associated with the plasma membrane of infected cells. Myristic acid is bound in an amide linkage to glycine 2 of p60src. Of the N-terminal 30 kilodaltons of p60src, only amino acids 1-14 are required for myristylation, and myristylation of p60src may be required for its membrane association, and for cell transformation. To test the hypothesis that the first 14 amino acids of p60src contain a recognition sequence for myristylation, we have fused the DNA sequence coding for these amino acids to either the fps gene of the F36 derivative of Fujinami sarcoma virus (FSV), or to the chimpanzee alpha-globin gene. We report here that although the fusion proteins were myristylated, the parental proteins were not, and unlike the non-myristylated F36 p91fps which was not bound to the plasma membrane, the myristylated fusion protein was bound, like p60src. We conclude that the first 14 amino acids of p60src contain a sequence which is sufficient for myristylation, and which may direct proteins to the plasma membrane.

Amino Acid Sequence↗
PubMedDate not supplied

Association of the polyomavirus middle-T antigen with c-yes protein.

Expression of the middle-T antigen of polyomavirus is sufficient to induce transformation of fibroblasts in culture and tumour formation in whole animals. Middle-T can form a complex with the cellular src gene product (p60c-src) and can be phosphorylated by p60c-src in vitro. Studies using middle-T mutants have suggested that the association of middle-T with p60c-src may be necessary but not sufficient for transformation. Therefore, we addressed the possibility that middle-T could interact with other tyrosine protein kinases structurally related to p60c-src. Using antibody raised against a fusion protein between beta-galactosidase and amino-terminal sequences of p90gag-yes from Y73 virus (anti-yes antibody), we have found that middle-T can associate with and be phosphorylated by the c-yes proto-oncogene product, a protein of relative molecular mass (Mr) 62,000 (62K). This raises the possibility that the middle-T-p62c-yes complex contributes to transformation by polyomavirus.

Antigens, Viral, Tumor↗