TY - JOUR A1 - Fritz, Michael Andre A1 - Rosa, Stefanie A1 - Sicard, Adrien T1 - Mechanisms Underlying the Environmentally Induced Plasticity of Leaf Morphology JF - Frontiers in genetics N2 - The primary function of leaves is to provide an interface between plants and their environment for gas exchange, light exposure and thermoregulation. Leaves have, therefore a central contribution to plant fitness by allowing an efficient absorption of sunlight energy through photosynthesis to ensure an optimal growth. Their final geometry will result from a balance between the need to maximize energy uptake while minimizing the damage caused by environmental stresses. This intimate relationship between leaf and its surroundings has led to an enormous diversification in leaf forms. Leaf shape varies between species, populations, individuals or even within identical genotypes when those are subjected to different environmental conditions. For instance, the extent of leaf margin dissection has, for long, been found to inversely correlate with the mean annual temperature, such that Paleobotanists have used models based on leaf shape to predict the paleoclimate from fossil flora. Leaf growth is not only dependent on temperature but is also regulated by many other environmental factors such as light quality and intensity or ambient humidity. This raises the question of how the different signals can be integrated at the molecular level and converted into clear developmental decisions. Several recent studies have started to shed the light on the molecular mechanisms that connect the environmental sensing with organ-growth and patterning. In this review, we discuss the current knowledge on the influence of different environmental signals on leaf size and shape, their integration as well as their importance for plant adaptation. KW - plants KW - leaf morphology KW - environment KW - developmental plasticity KW - gene regulatory networks KW - sensory system KW - gene responsiveness Y1 - 2018 U6 - https://doi.org/10.3389/fgene.2018.00478 SN - 1664-8021 VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Metzler, Ralf A1 - Bauer, Maximilian A1 - Rasmussen, Emil S. A1 - Lomholt, Michael A. T1 - Real sequence effects on the search dynamics of transcription factors on DNA JF - Scientific Reports N2 - Recent experiments show that transcription factors (TFs) indeed use the facilitated diffusion mechanism to locate their target sequences on DNA in living bacteria cells: TFs alternate between sliding motion along DNA and relocation events through the cytoplasm. From simulations and theoretical analysis we study the TF-sliding motion for a large section of the DNA-sequence of a common E. coli strain, based on the two-state TF-model with a fast-sliding search state and a recognition state enabling target detection. For the probability to detect the target before dissociating from DNA the TF-search times self-consistently depend heavily on whether or not an auxiliary operator (an accessible sequence similar to the main operator) is present in the genome section. Importantly, within our model the extent to which the interconversion rates between search and recognition states depend on the underlying nucleotide sequence is varied. A moderate dependence maximises the capability to distinguish between the main operator and similar sequences. Moreover, these auxiliary operators serve as starting points for DNA looping with the main operator, yielding a spectrum of target detection times spanning several orders of magnitude. Auxiliary operators are shown to act as funnels facilitating target detection by TFs. KW - gene regulatory networks KW - biological physics Y1 - 2015 U6 - https://doi.org/10.1038/srep10072 SN - 2045-2322 VL - 5 IS - 10072 PB - Nature Publishing Group CY - London ER -