2000 Fiscal Year Final Research Report Summary
Mechanism of no gene expression of hMLH1 in sporadic colorectal cancers : Identification of transcription factors and its establishment of detection method.
| Project/Area Number |
10671223
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Digestive surgery
|
|---|
| Research Institution | TOHO UNIVERSITY |
|---|
Principal Investigator |
HEMMI Hiromichi Toho Univ Sch Med, Dept Mol Biol, Assoc Prof, 医学部, 助教授 (90165514)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SHIMIZU Norikazu Toho Univ Sch Med, 2st Dept Pediatr, Asist Prof, 医学部, 講師 (60256740)
TSUJITA Kazunori Toho Univ Sch Med, 1st Dept Surg, Associate Prof, 医学部, 助教授 (60130374)
|
|---|
| Project Period (FY) |
1998 – 2000
|
| Keywords | mismatch repair gene / hMLH1 gene / colorectal cancer / transcription regulatory region / reporter gene assay / transcription factor / gel shift assay / in vivo footprinting |
|---|
| Research Abstract |
In 1993 and 1994, the hMSH2 and hMLH1 genes have been identified as responsible genes of hereditary nonpolyposis colorectal cancer (HNPCC). Defects of these genes are also associated with generation and development of many cancers. In this study, we focused in the mechanism of gene expression of hMLH1.
The major findings obtained during the project years are follows :
(1) Identification of promoter region essential for gene expression
By reporter gene analysis, a region containing -301 to -76 is essential for the gene expression.
(2) Protein binding regions and its consensus sequences for transcription factors
Six protein binding regions were identified by in vivo footprinting analysis. One CCAAT region was found by search program for transcription factor binding sites and protein binding to this site was confirmed by a get mobility shift assay. Among 7 sites, 3 sites were important for transcription. These results indicate that at least two or three regions are essential for the hMLH1 gene expression and also suggest that the factors may be unknown.
(3) Mutations in promoter region in sporadic colorectal cancer
When we searched the mutation in the promoter region of hMLH1 gene of tumor DNA of 90 sporadic colorectal cancer, 2 single nucleotide substitutions were found at -72 and -86. The former one is polymorphism, because same mutation was found in healthy population with high frequency. The later one was found in only cancer population and showed 70% of transcriptional activity compared to wild-type.
It is required for further investigation to identify the transcription factor(s) and its dysfunctional status in colorectal cancer.
|
