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Background | Radial Pattering
| Cell Expansion | Genomics
| At2010 |
Architecture | Other Projects |
Our analysis of cell division has focused on dissecting the mechanisms of radial patterning. We have identified mutations in Arabidopsis that result in roots that are missing one cell layer (Benfey et al., 1993) (Scheres et al., 1995). We have cloned the SCARECROW (SCR) and SHORTROOT (SHR) genes and determined that they encode members of the same family of putative transcription factors (Pysh et al., 1999). Their expression patterns are consistent with their proposed roles in radial patterning. Analyses of gene expression and cell identity indicate that SHR functions upstream of SCR and participates in a radial signaling pathway (Di Laurenzio et al., 1996). Consistent with a regulatory role in radial patterning, ectopic expression of SHR results in supernumerary cell divisions and abnormal cell specification in the root meristem (Helariutta et al., 2000). Recent work indicates that SHR protein is transported from the inner vascular cylinder (stele) to the surrounding endodermis. Thus SHR acts both as a directional signal and as an effector of downstream cell division and specification (Nakajima et al., 2001) |
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