Epidermal patterning in Arabidopsis: A novel patterning principle controlled by the basic helix-loop helix (bHLH) protein MYC1

Supervision: The project will be supervised by Martin Hülskamp at the University of Cologne.

Abstract: The correct temporal and spatial specification of specialized cell types in the plant epidermis is very important for the proper responses to environmental conditions. Trichomes in Arabidopsis thaliana are an ideal model system to study this developmental process called pattern formation. Genetic and molecular analysis indicates that trichomes are selected by lateral repression of trichome formation. The core of the gene regulatory network is the bHLH protein GL3. Competitive complex formation of other patterning proteins with GL3 governs the patterning process. Recently we discovered a new bHLH protein, MYC1, with a strikingly different molecular behavior suggesting the presence of two novel principles. First, the MYC1 protein regulates patterning by regulating the nuclear localization of the other proteins. Second, the current data suggest that the pattern is regulated by MYC1 by a threshold system in which the other patterning proteins can only act when their concentrations reach a certain concentration level. The project will involve a wide range of challenging genetic, molecular, cell biological, biochemical and modeling (in collaboration) approaches.

Link to the Hülskamp group homepage: https://huelskamp-lab.uni-koeln.de/

Top left: Arabidopsis thaliana rosette leaf with trichomes. Top right: MYC1 is localized in the whole cell (top picture) and only in the nucleus when co-expressed with TRY (bottom picture). Bottom scheme: MYC1 triggers nuclear import of TRY and nuclear export of GL1.
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