Project: Research project

Project Details


The long-term goal of these studies is to identify biochemical steps unique
to the transformed cell which might be amenable to interference by specific
pharmacological agents. Experiments are proposed which will help unravel
the cell's genetic and biochemical contributions to the process of
neoplastic transformation induced by the viral oncogene v-src. Cancer is
an intrinsically complex phenomenon which is poorly understood at the
molecular level. The current lack of understanding at the molecular level
has prevented such a directed pharmacological approach; commonly used drugs
attack all dividing cells, limiting the dose employed and inducing serious
side effects.

Three particular sets of experiments are proposed: (1) experiments
involving further characterization of the unique mutant allele v-src-L, and
the subsequent manipulation of v-src-L by further mutation; (2) experiments
to test the role of mitotic specific phosphorylations in the process of
transformation by v-src; and (3) (in collaboration with Dr. Harold Varmus,
UCSF) analysis of a unique set of mutant of v-src.

v-src-L transforms chicken but not rat cells; it is host-range dependent
for transformation. The pp60v-src-L protein encoded by v-src-L will be
characterized in detail for the Km and Vmax of the intrinsic tyrosine-
specific protein kinase activity against several substrates; preliminary
evidence suggests it exhibits a host-dependent substrate specificity (a
unique property among all oncogenes reported thus far). Proposed
biochemical and genetic experiments will address how this host-dependent
regulation is accomplished. Further experiments will identify the relevant
chicken and rat cellular genes involved in this regulation.

Site-directed mutagenesis will be used to analyze the necessity of mitosis-
specific phosphorylation of wt pp60v-src for (a) increased kinase activity
associated with pp60v-src during mitosis and (b) transformation by v-src.
Work by others in this field has focused on pp60c-src.

Finally, a collection of naturally occurring, biologically selected v-src
alleles (generated by H. Varmus) will be analyzed with regard to sequence
in order to search for domains of pp60v-src which are critical for
transformation. This collection of mutants is unique in that each member
is (a) naturally occurring (implying no investigator bias), and (b) a point
mutant (implying a relatively subtle lesion).
Effective start/end date7/10/906/30/97


  • National Cancer Institute
  • National Cancer Institute
  • National Cancer Institute
  • National Cancer Institute


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