In both plants and animals Polycomb group (PcG) genes act to maintain silencing of key developmental genes. A number of PcG genes have been identified in <i>Arabidopsis</i> through independent genetic screens. These can be placed in three groups based upon strong homology with the <i>Drosophila </i>proteins E(z), ESC and SU(Z)12. <i>Arabidopsis</i> contains multiple homologues of E(z) and these have evolved to act in different pathways (<i>CURLY LEAF</i> represses flowering in the immature plant; <i>MEDEA</i> prevents certain aspects of seed development in the absence of fertilisation; and <i>CURLY LEAF LIKE</i> has recently been shown to be partially redundant to <i>CLF</i>). Despite the high level of conservation between CLF and MEA proteins, I have shown that they are not equivalent. <i>MEA</i> is unable to rescue a <i>clf- </i>when expressed under either the <i>CLF</i> endogenous promoter or the constitutative 35S promoter. In <i>Drosophila</i> it has been shown that E(Z) acts in multimeric protein complexes with the PcG proteins ESC and SU(Z)12. Through yeast-two hybrid assays I have shown that CLF physically interacts with both the SU(Z)12 homologue EMF2 and the ESC homologue FIE, providing evidence of a similar complex acting to repress flowering in the immature plant. I have mapped the domains to which these interactions mediate. Of particular interest is the interaction between EMF2 and CLF; this region maps to the VEFS box of EMF2 and the C5 region of CLF. Embryos carrying a maternal inherited <i>fie</i> allele abort during deed development, making it impossible to observe the role of <i>FIE</i> post seed development. I have created a transgenic steroid-inducible <i>FIE </i>line, which I have used to rescue <i>fie</i>- embryos. The resulting plants show severe developmental abnormalities, with highly disorganised organ growth.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:641651 |
| Date | January 2004 |
| Creators | Bishopp, Anthony |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11985 |
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