Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. STKE, 3 October 2000
Vol. 2000, Issue 52, p. tw7
[DOI: 10.1126/stke.2000.52.tw7]

EDITORS' CHOICE

Nuclear Lipids Transcriptional Regulation by the Nuclear Phosphoinositide Cycle

The role of the nuclear phosphoinositide cycle remains an unanswered question. Bunney et al. perform careful biochemical analysis of the phosphoinositide species formed from nuclei isolated from plants and show that the phosphatidylinositol 4-kinase (PI4K) activity is extracted with detergents and the phosphatidylinositol 3-kinase (PI3K) activity remains in detergent-resistant or inaccessible structures. Furthermore, an antibody against soybean PI3K recognizes a nuclear epitope that colocalizes with sites of active transcription identified by incorporation of bromo-uracil triphosphate. A second group, Faenza et al., studied the effect of overexpression of two differentially distributed isoforms of phospholipase C-β1 [PLC-β1a (nuclear and cytoplasmic) and PLC-β1b (nuclear)] on progression through the cell cycle in mammalian cells. Overexpression of either of these two isoforms resulted in increased expression of cyclin D3 and cyclin-dependent kinase 4, promoted phosphorylation of retinoblastoma protein (Rb), and increased the DNA-binding activity of E2F even under conditions in which the wild-type cells do not exhibit these characteristics. Each of these effects was eliminated when the nuclear targeting signal of PLC-β1b was inactivated. Together these two papers point to a role for the nuclear phosphoinositide cycle in the regulation of transcription.

Bunney, T.D., Watkins, P.A.C., Beven, A.F., Shaw, P.J., Hernandez, L.E., Lomonossof, G.P., Shanks, M., Peart, J., and Drøbak, B.K. (2000) Association of phosphatidylinositol 3-kinase with nuclear transcription sites in higher plants. Plant Cell 12: 1679-1687. [Abstract] [Full Text]

Faenza, I., Matteucci, A., Manzoli, L., Billi, A.M., Aluigu, M., Peruzzi, D., Vitale, M., Castorina, S., Suh, P.G., and Cocco, L. (2000) A role for nuclear phospholipase Cβ1in cell cycle control. J. Biol. Chem. 275: 30520-30524. [Abstract] [Full Text]

Citation: Transcriptional Regulation by the Nuclear Phosphoinositide Cycle. Sci. STKE 2000, tw7 (2000).


To Advertise     Find Products


Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882