One GeneTwo Functions Model

If a gene has a positive role in cell proliferation and a negative role in post-mitotic cell expansion, the loss of function and overexpression of this gene should produce phenotypes identical to, and opposite, those in compensation-exhibiting mutants, respectively. If this is the case, systems that integrate cell proliferation and cell enlargement are not needed to interpret compensation. However, our present knowledge of the nature of responsive genes in compensation-exhibiting mutants eliminates the possibility of the one-gene-two-functions model. Namely, these genes, such as AN3 and ANT, seem to be involved exclusively in the control of cell proliferation. For example, the overexpression of AN3 and ANT promotes cell proliferation but has no influence on cell expansion (Mizukami and Fischer 2000; Horiguchi et al. 2005). In addition, AN3, ANT, FASCIATA1 (FAS1), and SWELLMAP (SMP), which induce compensation when mutated, are expressed strongly in meristematic tissues but at an undetectable level in differentiating tissues (Elliott et al. 1996; Kaya et al. 2001; Autran et al. 2002; Clay and Nelson 2005; Horiguchi et al. 2005; Exner et al. 2006). Thus, the one-gene-two-function model does not hold for at least several instances of compensation.

0 0

Post a comment