Project: Research project

Project Details


A number of immediate-early (IE) genes which constitute the primary
genomic response to growth stimuli have been identified, including a
novel gene, HLH462. HLH462 encodes a protein containing a
helix-loop-helix (HLH) domain similar to that found in a class of
transcriptional regulatory molecules important in cellular
differentiation and embryonic development. The hypothesis that the
protein product of the HLH462 gene plays an important role in the control
of growth and development will be tested in four specific aims. First,
the temporal and spatial pattern of HLH462 gene and protein expression in
mouse embryos will be determined using the methods of in situ
hybridization and immunohistochemistry with probes specific for HLH462.
Second, specific antibody reagents will be generated and purified, and
the biochemical and biological properties of the HLH462 protein will be
investigated. Since the HLH462 gene structure predicts that the protein
product contains an HLH domain which is known to be important for
protein-protein interactions, the third aim of this proposal is to
identify other known or unknown HLH proteins which are able to interact
with the HLH462 protein. In vitro translated proteins derived from other
cloned HLH genes will be tested for their ability to interact with
purified recombinant HLH462 protein and for their ability to be co-
immunoprecipitated with HLH462 antibodies. Proteins which interact with
HLH462 in these assays will be further investigated. Genes encoding
uncharacterized proteins which can interact with HLH462 can be cloned by
using labeled recombinant HLH462 protein as a molecular probe. The
fourth aim of the proposed research is to test the hypothesis that HLH462
protein is necessary for growth regulation in cultured cells. The normal
pattern of expression of HLH462 in these cells will be disturbed in order
to assay the effects on growth and the response to growth stimulation.
To inhibit the induction of HLH462, antisense RNA expression constructs
and antisense oligonucleotides will be employed. In addition,
anti-HLH462 antibodies will be injected into cells in order to neutralize
the activity of the protein. The ability of overexpressed HLH462 protein
to confer a growth advantage or disadvantage on fibroblast cells will
also be assayed. It is expected that these experiments will determine
whether the induction of HLH462 (a growth-associated gene) is necessary
for cell growth. The determination of the sites of HLH462 expression,
characterization of the protein's properties, identification of protein
partners and determination of the effects of HLH462 on cell growth
regulation will be important for understanding the role of HLH462 in the
control of normal and abnormal growth and development and disease states
which involve regulation of these processes.
Effective start/end date1/1/9312/31/97


  • National Institutes of Health: $99,325.00
  • National Institutes of Health: $92,494.00


  • Medicine(all)


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