Plants, unlike animals, possess a unique developmental plasticity, that allows them to adapt to changing environmental conditions. A fundamental aspect of this plasticity is their ability to undergo postembryonic de novo organogenesis. This requires the presence of regulators that trigger and mediate specific spatiotemporal changes in developmental programs. The phytohormone cytokinin has been known as a principal regulator of plant development for more than six decades. In de novo shoot organogenesis and in vitro shoot regeneration, cytokinins are the prime candidates for the signal that determines shoot identity. Both processes of de novo shoot apical meristem development are accompanied by changes in gene expression, cell fate reprogramming, and the switching-on of the shoot-specific homeodomain regulator, WUSCHEL. Current understanding about the role of cytokinins in the shoot regeneration will be discussed.

• Klíčová slova
• cytokinin, de novo organogenesis, plant stem cells, shoot apical meristem, shoot regeneration,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Histidine-containing phosphotransfer proteins from Arabidopsis thaliana (AHP1-5) act as intermediates between sensor histidine kinases and response regulators in a signalling system called multi-step phosphorelay (MSP). AHP proteins mediate and potentially integrate various MSP-based signalling pathways (e.g. cytokinin or osmosensing). However, structural information about AHP proteins and their importance in MSP signalling is still lacking. To obtain a deeper insight into the structural basis of AHP-mediated signal transduction, the three-dimensional structure of AHP2 was determined. The AHP2 coding sequence was cloned into pRSET B expression vector, enabling production of AHP2 fused to an N-terminal His tag. AHP2 was expressed in soluble form in Escherichia coli strain BL21 (DE3) pLysS and then purified to homogeneity using metal chelate affinity chromatography and anion-exchange chromatography under reducing conditions. Successful crystallization in a buffer which was optimized for thermal stability yielded crystals that diffracted to 2.5 Å resolution.

• Klíčová slova
• AHP2, Arabidopsis thaliana, histidine phosphotransfer proteins, multi-step phosphorelay,
• MeSH
• Arabidopsis metabolismus   MeSH
• difrakce rentgenového záření MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• fosfotransferasy chemie   izolace a purifikace   MeSH
• krystalizace MeSH
• proteiny huseníčku chemie   izolace a purifikace   MeSH
• signální transdukce * MeSH
• tranzitní teplota MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AHP2 protein, Arabidopsis MeSH Prohlížeč
• fosfotransferasy MeSH
• proteiny huseníčku MeSH