Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Suppression of Mouse Mammary Tumor Proviral DNA and Protooncogene Expression: Association with Nutritional Regulation of Mammary Tumor Development

Rou-Fuie Chen, Robert A. Good, Robert W. Engelman, Nobuyuki Hamada, Akiko Tanaka, Meihan Nonoyama and Noorbibi K. Day
Proceedings of the National Academy of Sciences of the United States of America
Vol. 87, No. 7 (Apr., 1990), pp. 2385-2389
Stable URL: http://www.jstor.org/stable/2354226
Page Count: 5
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Suppression of Mouse Mammary Tumor Proviral DNA and Protooncogene Expression: Association with Nutritional Regulation of Mammary Tumor Development
Preview not available

Abstract

$\smash{/}{c}$ Chronic energy intake restriction (CEIR) reduces mouse mammary tumor virus (MMTV)-induced mammary tumors in C3H/Ou mice. Fewer than 10% of C3H/Ou mice developed mammary tumors during 88 wk of study when subjected to CEIR regardless of calorie source (fat vs. carbohydrate). By contrast, 100% of mice fed ad libitum diets relatively high in fat or carbohydrate or a commercial diet developed tumors by 35-40 wk. MMTV proviral DNA transcription was shown to be activated in spleen, liver, lung, kidney, small intestine, and mammary gland of mice consuming these diets ad libitum. By contrast, these messages were suppressed by CEIR in all tissue analysed except spleen. MMTV proviral messages in liver and mammary gland increased with age in full-fed mice and were suppressed by CEIR. These findings suggest that the nutritional regulation of MMTV proviral DNA expression is tissue specific. In CEIR mice the suppressed MMTV provical DNA transcripts in mammary gland and liver increased with time in association with the delayed onset of mammary tumors. Mammary tumorigenesis in C3H mice is associated with integration of MMTV proviral DNA, which appears to activate a putative mammary tumor protooncogene, ∫-l. CEIR apparently decreases the frequency of viral reintegration adjacent to the int-l gene and thus inhibits expression of ∫-1 and probably an initiation step in mammary tumorigenesis. Expression of other putative protooncogenes, int-2 and ras, in liver tissue was also reduced by CEIR. These findings indicate that both initiation and promotion of mammary tumorigenesis are influenced by CEIR in C3H/Ou mice.

Page Thumbnails

  • Thumbnail: Page 
2385
    2385
  • Thumbnail: Page 
2386
    2386
  • Thumbnail: Page 
2387
    2387
  • Thumbnail: Page 
2388
    2388
  • Thumbnail: Page 
2389
    2389