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| Assistant Professor |
| Office:
919-966-6921 |
| E-mail:
jayne_boyer@med.unc.edu |
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| I
am collaborating with Dr. Rosann Farber on molecular mechanisms
of microsatellite instability. Microsatellites are repetitive
DNA sequences in which the number of bases in a repeat unit
can number from 1-6 bases. [e.g., AN is an example of a mononucleotide
repeat and (GAAA)N is an example of a tetranucleotide repeat
with N number of repeats]. Tracts can vary up to 30 repeat
units in length. Microsatellites are widely dispersed throughout
the eukaryotic genome. Many microsatellites are polymorphic
in the human population, in that there are differences in the
numbers of repeats among alleles. Instability in microsatellites
has been attributed to a DNA polymerase slippage mechanism
first proposed by Streisinger et al. These sequences are exceptionally
unstable in cells lacking mismatch repair. This instability
is evident in tumors of patients with HNPCC (hereditary nonpolyposis
colorectal cancer) and in the 10-15% of sporadic colorectal
and endometrial cancers that are mismatch-repair deficient.
We have developed a selective system in which to measure
mutation rates in microsatellites in cultured cells. In our
system, the mutation target is a repeat contained within
a stably integrated plasmid. The repeat disrupts the reading
frame of a neomycin-resistance gene within the plasmid. Cells
containing frameshift mutations in the repeat that correct
the reading frame of the neomycin gene are selected using
the neomycin analog G418. This system of measuring microsatellite
mutation rates is highly sensitive because there is a specific
target within which mutations can be selected. Mutation rates
are measured by fluctuation analysis, and the types of mutations
are determined by PCR and DNA sequencing. Using this system
we can compare mutation rates and mutation spectra in normal
and neoplastic cells and cells with or without mismatch repair.
Much of our research has focused on the properties of microsatellites
that may affect their mutation rate. These include: 1) length
of the repeat unit (e.g., mono- vs. dinucleotides), 2) base
composition of the repeat, 3) number of repeat units per
tract, 4) degree of perfection of repeats (i.e., presence
or absence of interruptions in the tract), and 5) composition
of flanking sequences.
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| Hawk, JD, Stephanovic, L., Boyer, JC, Petes, TD, and Farber,
RA. Variation of efficiency of mismatch repair at different
sites in the yeast genome. Proc. Natl. Acad. Sci., USA 2005;
102: 8639-8643. |
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| Yamada, NA, Smith, GA, Castro, A, Roques, CN, Boyer, JC, and
Farber, RA. Relative rates of insertion and deletion mutations
in dinucleotide repeats of various lengths in mismatch repair
proficient mouse and mismatch deficient human cells. Mutation
Res. 2002; 499: 213-225. |
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| Boyer, JC, Yamada, NA, Reiss, K, Hatch, SB, and Farber, RA.
Mutation rates of mononucleotide microsatellite sequences in
mismatch repair proficient- and deficient-cell lines, Human
Molecular Genetics , 2002; 11: 707-713. |
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| Yamada, NA, Smith, GA, Castro, A, Roques, CN, Boyer, JC, and
Farber, RA,. Relative rates of insertions and deletion mutations
in dinucleotide repeats of various lengths in mismatch-repair
proficient mouse and mismatch repair deficient mammalian cells,
Mutation Res. 2001; 499: 213-225. |
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| Roques, CN, Boyer, JC, and Farber, RA,. Microsatellite mutation
rates are equivalent in normal and telomerase-immortalized
fibroblasts. Cancer Research, 2001; 61:8405-8407. |
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| Bebenek, K, Boyer, JC, and Kunkel, TA,. The base substitution
fidelity of HIV-1 reverse transcriptase on DNA and RNA templates
probed with 8-oxo-deoxyguanosine. Mutation Research/Fundamental
and Molecular Mechanisms of Mutagenesis. 1999; 429:149-58. |
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| Twerdi, CD, Boyer, JC, and Farber, RA, Relative rates of insertion
and deletion mutations in a microsatellite sequence in cultured
cells. Proceedings of the National Academy of Sciences, USA,
1999; 96: 2875-2879. |
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| Boyer, JC and Farber, RA, Mutation rate of a microsatellite
sequence in normal human fibroblasts. Cancer Research, 1998;
58: 3946-3949. |
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| Boyer, JC, Risinger, JI, and Farber, RA, Stability of microsatellites
in myeloid neoplasia. Cancer Genetics and Cytogenetics, 1998;
106: 54-61. |
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| Boyer, JC, Umar, A, Risinger, JI, Lipford, R, Kane, M, Barrett,
JC, Kolodner, RD, and Kunkel, TA, Microsatellite instability,
mismatch repair deficiency and genetic defects in human cancer
cells. Cancer Research, 1995; 55: 6063-6070. |
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| Risinger, JI, Umar, A, Boyer, JC, Evans, AC, Berchuck, A,
Kunkel, TA, and Barrett, JC, Microsatellite instability in
gynecologic sarcomas and in hMSH2 mutant uterine sarcoma cell
lines defective in mismatch repair activity. Cancer Research,
1995; 55: 5664-5669. |
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| Umar, A, Boyer, JC, and Kunkel, TA, DNA loop repair by human
cell extracts. Science, 1994; 266: 814-816. |
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| Umar, A, Boyer, JC, Thomas, DC, Nguyen, D, Risinger, JI, Boyd,
J, Ionov, Y, Perucho, M, and Kunkel, TA, Defective mismatch
repair in extracts of colorectal and endometrial cancer cells
lines exhibiting microsatellite instability. The Journal of
Biological Chemistry, 1994; 269: 14367-14370. |
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| Boyer, JC, Thomas, DC, Maher, VM, McCormick, JJ and Kunkel,
TA, Fidelity of DNA replication by extracts of normal and malignantly
transformed human cells, Cancer Research, 1993; 53: 3270-3275. |
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| Boyer, JC, Bebenek, K, and Kunkel, TA, Unequal HIV-1 reverse
transcriptase error rates with RNA and DNA templates, Proc.
Natl. Acad. Sci, USA, 1992; 89: 6919-6923. |
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| Kaufmann, WK, Boyer, JC, Estabrook, L, and Wilson, SR, Inhibition
of replicon initiation in human cells following freezing of
topoisomerase-DNA cleavable complexes. Molecular and Cellular
Biology, 1991; 11: 3711-3718. |
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| Boyer, JC, Kaufmann, WK, and Cordeiro-Stone, M, The role of
postreplication repair in transformation of human fibroblasts
to anchorage independence, Cancer Research, 1991; 51: 2960-2964. |
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| Boyer, JC, Kaufmann, WK, Brylawski, BP, and Cordeiro-Stone,
M, Defective postreplication repair in xeroderma pigmentosum
variant fibroblasts. Cancer Res. , 1990; 50: 2593-2598. |
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| Kaufmann, W.K., Boyer, J.C. and Cordeiro-Stone, M. Pathways
of human DNA metabolism and carcinogenesis. Toxicologic Path.17:
829-830, 1989. |
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| Cordeiro-Stone, M, Boyer, JC, Smith, BA, and Kaufmann, WK,
Xeroderma pigmentosum variant and normal fibroblasts show
the same response to the inhibition of DNA replication by
benzo[a]pyrene-diol-epoxide-I. Carcinogenesis , 1986; 7:
1783-1786. |
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| Cordeiro-Stone, M, Boyer, JC, Smith, BA, and Kaufmann, WK, Effect
of benzo[a]pyrene-diol-epoxide-I on growth of nascent DNA in
synchronized human fibroblasts. Carcinogenesis, 1986; 7: 1775-1781. |
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| Kaufmann, WK, Boyer, JC, Smith, BA, Cordeiro-Stone, M,
DNA repair and replication in human fibroblasts treated
with BPDE-I.
Biochimica
Biophysica Acta, 1985; 824: 146-151. |
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| Gealt,
MA, Chai, MD, Alpert, KB and Boyer, JC, Transfer of plasmids
pBR322 and pBR325 in wastewater from laboratory strains of
Escherichia coli to bacteria indigenous to the waste disposal
system. Applied and Environmental Microbiology, 1985; 49: 836-841. |
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