|
 |
|
EDRI Federal Project Inventory:
61319-02 Metallothionein–Effects on Mutagenesis
- Sponsor Organization: NIH/NCI
- Project Title: 61319-02 METALLOTHIONEIN--EFFECTS ON MUTAGENESIS
- Project Focus: HUMAN HEALTH EFFECTS
- Description: The main goal of this proposal is to test the hypothesis that
metallothionein (MT) is able to effect the level of themutagenic
events induced by genotoxic carcinogens. There is some contradictory
data concerning the sensitivity of cellswith varying levels of MT
expression sensitivity to the toxic effects of carcinogens and
chemotherapeutic agents. However, no studies have yet been carried
out on mutation frequencies in such cells. We have developed a series
ofChinese hamster V79-transgenic cell lines containing single copies
of the E. coli gpt gene. One of these, G12, has beenshown have a
target gene (gpt) which is normally mutable by alkylating agents and
highly mutable by agents causingoxidative damage (e.g. x-rays) which
do not produce many gene mutations in most systems. Like many
permanent celllines, G12 has a low level of constitutive and induced
MT expression. We have used G12 cells to create MT-overproducing
cells by transfection of a mouse MT-I gene in a pBPV vector.
Preliminary results show that the MTtransfectant with the highest
level of expression has an elevated spontaneous mutation frequency
compared to its parent,G12. However, these results are confounded by
the presence of extrachromosomally replicating plasmid, which
mightconfer genetic instability. We propose to construct transgenic
lines, using G12 as host, which contain stably integratedcopies of
mouser MT-I. In addition, we will create an MT anti-sense expression
vector in order to knock out host MT-Iexpression. These lines will be
used to measure the spontaneous mutation frequency as well as the
induced mutagenesisafter treatment with a number of metal (crystalline
nickel sulfate and calcium chromate), physical (UV and x-rays)
andorganic (MNU and MNNG) carcinogens and chemotherapeutic agents
(cisplatin, bleomycin, mAMSA). The abilitiesof arsenite, Cd(II), and
Pb(II) to act as comutagens will also be evaluated. If effects on
mutagenesis or comutagenesisare found to vary with MT expression,
effects of MT levels on DNA repair enzymes (which require zinc) will
be studiedin permeabilized cells.
- References:
- Category: MODELS
- Subcategory: BASIC RESEARCH
- Keywords for Experimental System/Species: MAMMALIAN, LABORATORY STUDY
- Keywords for Experimental Endpoints: TRANSGENIC MODEL
- Chemical Agents: NICKEL, HEAVY METALS, LEAD, CADMIUM
- Performing Institution: NEW YORK UNIVERSITY
- Contact: CONTRACT PERSON: ELAINE C. LEE; BUILDING 31; 11A21; NATIONAL CANCER
INSTITUTE, NIH,BETHESDA, MD 20892-2590; 301-496-5515;
LEEE@OD.NCI.NIH.GOV
|
|
