Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download valve margin
Document related concepts
Transcript
Patterning the Arabidopsis fruit Arabidopsis fruit structure valve margin valve replum Arabidopsis fruit opening valve margin valve replum seed Fruit dehiscence promotes seed dispersal valve valve Genes involved in seed dispersal in Arabidopsis can control loss of yield in oilseed crops Note that DZ = Valve Margin Genes Controlling Fruit Development ? ? ? replum valve valve margin SHATTERPROOF (SHP) gene is required for valve margin formation wild type shp Genes Controlling Fruit Development ? SHP ? replum valve valve margin IND and SHP are required for valve margin formation wild type ind shp IND is expressed in stripes at the valve margin and is positively regulated by SHP valve margin replum wild type valve shp Genes Controlling Fruit Development SHP ? IND ? replum valve valve margin How is SHP and IND expression limited to the valve margin? SHP IND ? ? replum valve valve margin FRUITFULL (FUL) transcription factor is required for valve cells Valve cells wild type wild ful type ful FUL is expressed in valve cells SHP and IND are ectopically expressed in ful mutant valves valve Wild type valve ful mutant IND expression SHP and IND are negatively regulated by FUL in the valves Wild type ful mutant IND expression Is the fruitfull mutant phenotype caused by ectopic expression of the valve margin (SHP, IND) genes? The failure of ful-mutant fruit to elongate is restored by mutations in shp and ind Wild type shp ind ful ind1 ful shp ful ful The fruitfull mutant phenotype is caused by mis-expression of SHP and IND Wild type shp ind ful ind ful shp ful ful “Valve” is the “default” state FUL is expressed in valve cells where it functions to negatively regulate SHP and IND SHP IND FUL ? replum valve margin valve enb replumless (rpl) mutant fails to form a replum Wild type replum rpl RPL encodes a homeobox protein and is expressed in the replum RPL Are SHP and IND ectopically expressed in the rpl mutant replum? IND is ectopically expressed in the rpl mutant replum VM VM R wild type rpl mutant IND expression Is the replumless mutant phenotype caused by the ectopic expression of the valve margin genes? Mutations in SHP rescue rpl Wild type rpl rpl shp RPL is expressed in the replum and functions to negatively regulated SHP and IND SHP IND FUL RPL replum valve valve margin What happens in the ful rpl double mutant? SHP IND FUL RPL replum valve valve margin All valve margin: rpl ful valve replum valve SHP and IND are expressed In the valve, valve margin and replum regions in rpl ful mutants rpl ful Genes controlling fruit development? SHP IND FUL RPL replum valve valve margin The FUL gene is normally expressed in valves replum valve What happens if the FUL gene is mis-expressed in all cells of the fruit? wild type mis-expression of FRUITFULL converts replum and valve margin cells into valve cells replum valve wild type 35S::FUL D/V Signaling Is Required for Wing Margin Formation and Wing Outgrowth Ap -> Notch -> Wing Margin = D/V Organizer D V D/V Organizer -> Margin Formation and Wing Growth Activation of Notch Along ap Expressing Cells Future Margin D ->V Signal Loss of ap in Dorsal Cells -> Margin Formation ap - cells V -> D Signal ap Non-expressing Cells Wing imaginal disc in larva Adult wing (viewed end on) Adult wing withap- patch Fig. 4.4 •Interactions between cells on the dorsal and ventral surfaces of leaves result in the formation of a leaf margin, which is required for leaf outgrowth. Phantastica mutants, like apterous mutants in flies, cannot form the dorsal surface of leaves. •Loss of phantastica function leads to loss of leaf outgrowth. •Partial loss of phantastica function leads to narrow leaves that are cupped upwards due to fewer dorsal cells. •Phantastica mutants illustrate that leaf outgrowth requires interactions between dorsal and ventral cells. •Weak phantastica mutants can have “islands” of ventral cells on the dorsal surface. •Marginal structures form at the border between dorsal and ventral cells. Conclusions •In flies and plants, juxtaposition of dorsal and ventral surfaces induces formation of an organizing margin. •The organizing margin controls outgrowth of the appendage.
