Plant biology

Which Way Is Up?

Science's STKE  13 Jun 2006:
Vol. 2006, Issue 339, pp. tw202
DOI: 10.1126/stke.3392006tw202

Plants need to determine which end is "up" long before they emerge as seedlings from the ground. For Arabidopsis, the first indications of an apical-basal axis are seen in the initial embryonic cell division that separates a smaller apical cell from a larger basal cell. These cells generally go on to form shoots or roots. Long et al. have now cloned the Topless gene, mutations in which can alter the fate of the apical pole. The Topless protein bears features that resemble transcriptional corepressors. Mutations in a histone deacetylase affect Topless function, and thus chromatin remodeling likely plays a key role. These findings suggest that auxin-mediated axis formation precedes transcription-mediated axis stabilization.

J. A. Long, C. Ohno, Z. R. Smith, E. M. Meyerowitz, TOPLESS regulates apical embryonic fate in Arabidopsis. Science 312, 1520-1523 (2006). [Abstract] [Full Text]