Identification and expression analysis of OsHsfs in rice*

Heat stress transcription factors (Hsfs) are the central regulators of defense response to heat stress. We identified a total of 25 rice Hsf genes by genome-wide analysis of rice (Oryza sativa L.) genome, including the subspecies of O. japonica and O. indica. Proteins encoded by OsHsfs were divided into three classes according to their structures. Digital Northern analysis showed that OsHsfs were expressed constitutively. The expressions of these OsHsfs in response to heat stress and oxidative stress differed among the members of the gene family. Promoter analysis identified a number of stress-related cis-elements in the promoter regions of these OsHsfs. No significant correlation, however, was found between the heat-shock responses of genes and their cis-elements. Overall, our results provide a foundation for future research of OsHsfs function

Functional ecological genomics to demonstrate general and specific responses to abiotic stress.

1. Stress is a major component of natural selection in soil ecosystems. The most prominent abiotic stress factors in the field are temperature extremes (heat, cold), dehydration (drought), high salinity and specific toxic compounds such as heavy metals. Organisms are able to deal with these stresses to a certain extent, which determines the limits of their ecological amplitudes. Functional genomic tools are now becoming available to study stress in ecologically relevant soil organisms. 2. Here we give an overview of transcriptomic studies aiming to elucidate how plants and soil invertebrates respond and adapt to a stressful environment. The picture emerging from signalling pathways and transcription factors identified in transcription profiling studies suggests that there is a large overlap of genomic responses to drought, salinity and cold; however, heat and heavy metals trigger different stress response pathways. 3. The heat shock response and the oxidative stress response seem to represent universal components of the environmental stress response (ESR). Furthermore, the commonality across plants and animals seems to be higher in effector genes than in transcriptional regulators. 4. Finally, adaptation to stress factors in soil seems to evolve through enhanced constitutive transcription of otherwise stress responsive genes both in plants and animal

Controlled expression of recombinant proteins in Physcomitrella patens by a conditional heat-shock promoter: a tool for plant research and biotechnology.

The ability to express tightly controlled amounts of endogenous and recombinant proteins in plant cells is an essential tool for research and biotechnology. Here, the inducibility of the soybean heat-shock Gmhsp17.3B promoter was addressed in the moss Physcomitrella patens, using beta-glucuronidase (GUS) and an F-actin marker (GFP-talin) as reporter proteins. In stably transformed moss lines, Gmhsp17.3B-driven GUS expression was extremely low at 25 degrees C. In contrast, a short non-damaging heat-treatment at 38 degrees C rapidly induced reporter expression over three orders of magnitude, enabling GUS accumulation and the labelling of F-actin cytoskeleton in all cell types and tissues. Induction levels were tightly proportional to the temperature and duration of the heat treatment, allowing fine-tuning of protein expression. Repeated heating/cooling cycles led to the massive GUS accumulation, up to 2.3% of the total soluble proteins. The anti-inflammatory drug acetyl salicylic acid (ASA) and the membrane-fluidiser benzyl alcohol (BA) also induced GUS expression at 25 degrees C, allowing the production of recombinant proteins without heat-treatment. The Gmhsp17.3B promoter thus provides a reliable versatile conditional promoter for the controlled expression of recombinant proteins in the moss P. patens

The Arabidopsis Nuclear Pore and Nuclear Envelope

The nuclear envelope is a double membrane structure that separates the eukaryotic cytoplasm from the nucleoplasm. The nuclear pores embedded in the nuclear envelope are the sole gateways for macromolecular trafficking in and out of the nucleus. The nuclear pore complexes assembled at the nuclear pores are large protein conglomerates composed of multiple units of about 30 different nucleoporins. Proteins and RNAs traffic through the nuclear pore complexes, enabled by the interacting activities of nuclear transport receptors, nucleoporins, and elements of the Ran GTPase cycle. In addition to directional and possibly selective protein and RNA nuclear import and export, the nuclear pore gains increasing prominence as a spatial organizer of cellular processes, such as sumoylation and desumoylation. Individual nucleoporins and whole nuclear pore subcomplexes traffic to specific mitotic locations and have mitotic functions, for example at the kinetochores, in spindle assembly, and in conjunction with the checkpoints. Mutants of nucleoporin genes and genes of nuclear transport components lead to a wide array of defects from human diseases to compromised plant defense responses. The nuclear envelope acts as a repository of calcium, and its inner membrane is populated by functionally unique proteins connected to both chromatin and—through the nuclear envelope lumen—the cytoplasmic cytoskeleton. Plant nuclear pore and nuclear envelope research—predominantly focusing on Arabidopsis as a model—is discovering both similarities and surprisingly unique aspects compared to the more mature model systems. This chapter gives an overview of our current knowledge in the field and of exciting areas awaiting further exploration