Abstract
Colon cancer and an increasing number of other cancers have been found to exhibit instability of DNA microsatellite sequences. Such tumors have been designated as replication errors (RER) tumors. However, as microsatellites are only rarely found within coding regions of the genome, instability of these sequences cannot directly contribute to carcinogenesis. Recently, we have shown RER colon cancers also demonstrate a marked 100-fold increase in mutation rates measured within an expressed gene, hprt, suggesting the mutator phenotype in these tumors extends beyond microsatellite sequences. To determine whether the RER phenotype indeed destabilizes non-repetitive DNA sequences we have sequenced hprt gene mutations recovered from the RER colon cancer cell line RKO. Greater than 10% of hprt mutants proved to be a single 3 bp deletion located in a nonrepetitive ATTAT sequence motif. Additionally, 1-4 bp deletions or insertions were found to be randomly located throughout the hprt gene. Lastly, one third of hprt mutations proved to be transitions or transversions. The microsatellite instability demonstrated in RKO is thus a global mutator phenotype which destabilizes DNA sequences both inside and outside of repetitive sequence elements and which augments base substitutions as well as frameshifts. These findings extend the characteristics of mutations associated with RER tumors and suggest additional mechanisms by which mutator phenotypes may alter target oncogenes and tumor suppressor genes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1425-1432 |
| Number of pages | 8 |
| Journal | Oncogene |
| Volume | 12 |
| Issue number | 7 |
| State | Published - 1996 |
| Externally published | Yes |
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Keywords
- Colon cancer
- Genomic instability
- HPRT
- Nucleic acid
- Repetitive sequences
- Replication errors (RER)
ASJC Scopus subject areas
- Molecular Biology
- Cancer Research
- Genetics
Cite this
Diverse hypermutability of multiple expressed sequence motifs present in a cancer with microsatellite instability. / Eshleman, James; Markowitz, Sanford D.; Donover, P. Scott; Lang, Evan Z.; Lutterbaugh, James D.; Li, Guo Min; Longley, Mathew; Modrich, Paul; Veigl, Martina L.; Sedwick, W. David.
In: Oncogene, Vol. 12, No. 7, 1996, p. 1425-1432.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Diverse hypermutability of multiple expressed sequence motifs present in a cancer with microsatellite instability
AU - Eshleman, James
AU - Markowitz, Sanford D.
AU - Donover, P. Scott
AU - Lang, Evan Z.
AU - Lutterbaugh, James D.
AU - Li, Guo Min
AU - Longley, Mathew
AU - Modrich, Paul
AU - Veigl, Martina L.
AU - Sedwick, W. David
PY - 1996
Y1 - 1996
N2 - Colon cancer and an increasing number of other cancers have been found to exhibit instability of DNA microsatellite sequences. Such tumors have been designated as replication errors (RER) tumors. However, as microsatellites are only rarely found within coding regions of the genome, instability of these sequences cannot directly contribute to carcinogenesis. Recently, we have shown RER colon cancers also demonstrate a marked 100-fold increase in mutation rates measured within an expressed gene, hprt, suggesting the mutator phenotype in these tumors extends beyond microsatellite sequences. To determine whether the RER phenotype indeed destabilizes non-repetitive DNA sequences we have sequenced hprt gene mutations recovered from the RER colon cancer cell line RKO. Greater than 10% of hprt mutants proved to be a single 3 bp deletion located in a nonrepetitive ATTAT sequence motif. Additionally, 1-4 bp deletions or insertions were found to be randomly located throughout the hprt gene. Lastly, one third of hprt mutations proved to be transitions or transversions. The microsatellite instability demonstrated in RKO is thus a global mutator phenotype which destabilizes DNA sequences both inside and outside of repetitive sequence elements and which augments base substitutions as well as frameshifts. These findings extend the characteristics of mutations associated with RER tumors and suggest additional mechanisms by which mutator phenotypes may alter target oncogenes and tumor suppressor genes.
AB - Colon cancer and an increasing number of other cancers have been found to exhibit instability of DNA microsatellite sequences. Such tumors have been designated as replication errors (RER) tumors. However, as microsatellites are only rarely found within coding regions of the genome, instability of these sequences cannot directly contribute to carcinogenesis. Recently, we have shown RER colon cancers also demonstrate a marked 100-fold increase in mutation rates measured within an expressed gene, hprt, suggesting the mutator phenotype in these tumors extends beyond microsatellite sequences. To determine whether the RER phenotype indeed destabilizes non-repetitive DNA sequences we have sequenced hprt gene mutations recovered from the RER colon cancer cell line RKO. Greater than 10% of hprt mutants proved to be a single 3 bp deletion located in a nonrepetitive ATTAT sequence motif. Additionally, 1-4 bp deletions or insertions were found to be randomly located throughout the hprt gene. Lastly, one third of hprt mutations proved to be transitions or transversions. The microsatellite instability demonstrated in RKO is thus a global mutator phenotype which destabilizes DNA sequences both inside and outside of repetitive sequence elements and which augments base substitutions as well as frameshifts. These findings extend the characteristics of mutations associated with RER tumors and suggest additional mechanisms by which mutator phenotypes may alter target oncogenes and tumor suppressor genes.
KW - Colon cancer
KW - Genomic instability
KW - HPRT
KW - Nucleic acid
KW - Repetitive sequences
KW - Replication errors (RER)
UR - http://www.scopus.com/inward/record.url?scp=9244258545&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=9244258545&partnerID=8YFLogxK
M3 - Article
C2 - 8622858
AN - SCOPUS:9244258545
VL - 12
SP - 1425
EP - 1432
JO - Oncogene
JF - Oncogene
SN - 0950-9232
IS - 7
ER -