Frequent activation of CArG binding factor-A expression and binding in N-methyl-N-nitrosourea-induced rat mammary carcinomas
Författare
Summary, in English
We previously identified a positive transcriptional element identical to human Ha-ras response element ( HRE) within the promoter of the rat Ha-ras gene. We further identified CArG binding factor A ( CBF-A), a member of heterogeneous nuclear ribonuclear protein ( hnRNP) gene family, as a trans-acting factor that binds the HRE sequence with high affinity in rat mammary carcinoma cells. To determine if activation of CBF-A plays a role in tumor development in vivo, we investigated CBF-A expression and binding activity in rat mammary tumors induced by N-methyl-N-nitrosourea. We found that -82% of tumors expressed CBFA at levels that were 3-20 fold higher than detected in normal mammary gland. Moreover, elevated CBF-A protein levels were invariably associated with increased binding activity to the HRE. CBF-A mRNA levels in tumors were on average elevated only two fold as compared to normal mammary gland, indicating that increased CBF-A protein levels in tumors resulted from both translational and/or post-translational regulation. The level of CBF-A expression in mammary tumors was independent of Ha-ras mutational status. Together, these findings indicated that deregulation of CBF-A contributes to mammary carcinogenesis via a mechanism that is distinct from its hnRNP functions in binding and post-transcriptional regulation of RNA.
Avdelning/ar
- Immunology
Publiceringsår
2004
Språk
Engelska
Sidor
95-102
Publikation/Tidskrift/Serie
Breast Cancer Research and Treatment
Volym
88
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
Springer
Ämne
- Cancer and Oncology
Nyckelord
- mammary tumor
- CArG binding factor A
- heterogeneous nuclear ribonuclear protein
- N-methyl-N-nitrosourea
Status
Published
Forskningsgrupp
- Immunology
ISBN/ISSN/Övrigt
- ISSN: 1573-7217