You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis 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.
Opposite Regulation of Gene Transcription and Cell Proliferation by c-Myc and Max
Wei Gu, Katarina Cechova, Vittorio Tassi and Riccardo Dalla-Favera
Proceedings of the National Academy of Sciences of the United States of America
Vol. 90, No. 7 (Apr. 1, 1993), pp. 2935-2939
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/2361653
Page Count: 5
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.
Preview not available
c-Myc and Max are nuclear phosphoproteins capable of forming DNA-binding, homo- and heteropolymeric complexes in vitro and in vivo. Using a transient cotransfection assay involving c-Myc and Max expression vectors and a reporter gene plasmid containing the Myc/Max binding site, we find that Max represses transcription, whereas a significant stimulation is obtained when Max is coexpressed with c-Myc. Analysis of specific mutants indicates that transcriptional activation requires both the c-Myc and the Max dimerization and DNA-binding domains, as well as the c-Myc transactivation function; transcriptional repression by Max requires both DNA binding and dimerization. Analogously, in stably transfected human B-lymphoblastoid cell lines, overexpressed c-Myc and Max synergize to cause malignant transformation, whereas overexpression of Max alone leads to growth inhibition. These results indicate that the c-Myc and Max are transcriptional regulators with the ability to oppositely regulate target-gene expression and cell proliferation, most likely as the result of the opposite effects of heterodimeric c-Myc-Max (positive) versus homodimeric Max (negative) complexes.
Proceedings of the National Academy of Sciences of the United States of America © 1993 National Academy of Sciences