Phenotypic modification of dorsal root ganglion (DRG) neuronsrepresents an important mechanism underlying neuropathic pain. However, the nerve injury-induced molecular changes are not fully identified. To determine the molecular alterations in a broader way, we have carried out cDNA array on the genes mainly made from the cDNA libraries of lumbar DRGs of normal rats and of rats 14 days after peripheral axotomy. Of the 7,523 examined genes and expressed sequence tags (ESTs), the expression of 122 genes and 51 expressed sequence tags is strongly changed. These genes encompass a large number of members of distinct families, including neuropeptides, receptors, ion channels, signal transduction molecules, synaptic vesicle proteins, and others. Of particular interest is the up-regulation of ␥-aminobutyric acidA receptor ␣5 subunit, peripheral benzodiazepine receptor, nicotinic acetylcholine receptor ␣7 subunit, P2Y1 purinoceptor, Na ؉ channel ␤2 subunit, and L-type Ca 2؉ channel ␣2␦-1 subunit. Our findings therefore reveal dynamic and complex changes in molecular diversity among DRG neurons after axotomy. N europathic pain is caused by nervous system lesions, persists long after the initiating event has healed, and may result from a pathological operation of the nervous system. Available therapies are often inadequate. Therefore, it is essential to identify the molecular changes that may lead to neuropathic pain, both for understanding underlying mechanisms and developing new therapies.The peripherally axotomized animal represents one model to study the mechanisms of neuropathic pain (1). After the finding that vasoactive intestinal polypeptide is up-regulated after axotomy (2), many subsequent studies have reported dramatic changes in individual molecules in dorsal root ganglion (DRG) after nerve injury, and some molecules are implicated in generation and maintenance of pain (3-5). For example, downregulation of -opioid receptor and up-regulation of cholecystokinin B receptor (6, 7) may contribute to the attenuated analgesic effect of opioids in neuropathic pain. Up-regulation of adrenoreceptor ␣2A (A-R␣2A) and neuropeptide Y (NPY) Y2-R enhances sympathetically maintained pain (8, 9). The increase in Na ϩ channel (Ch) III mediates ectopic activity in injured neurons (10). Moreover, hyperalgesia appearing during the course of nerve regeneration suggests a correlation between regeneration and pain. Neurotrophins play important roles in both nerve regeneration and regulation of the expression of some neuropeptides and ion channels (11,12). Taken together, current knowledge suggests that changes in gene expression in DRGs may contribute to the generation and development of neuropathic pain. However, although in situ hybridization and other methods have been extensively used to study the changes of individual genes in DRG, a limiting factor with these methods is the lack of a comprehensive overview of the alteration of gene expression. Here, we took a broader approach, a cDNA array (13), to gain a global view of the chang...

Pathogenic microbes use effectors to enhance susceptibility in host plants. However, plants have evolved a sophisticated immune system to detect these effectors using cognate disease resistance proteins, a recognition that is highly specific, often elicits rapid and localized cell death, known as a hypersensitive response, and thus potentially limits pathogen growth. Despite numerous genetic and biochemical studies on the interactions between pathogen effector proteins and plant resistance proteins, the structural bases for such interactions remain elusive. The direct interaction between the tomato protein kinase Pto and the Pseudomonas syringae effector protein AvrPto is known to trigger disease resistance and programmed cell death through the nucleotide-binding site/leucine-rich repeat (NBS-LRR) class of disease resistance protein Prf. Here we present the crystal structure of an AvrPto-Pto complex. Contrary to the widely held hypothesis that AvrPto activates Pto kinase activity, our structural and biochemical analyses demonstrated that AvrPto is an inhibitor of Pto kinase in vitro. The AvrPto-Pto interaction is mediated by the phosphorylation-stabilized P+1 loop and a second loop in Pto, both of which negatively regulate the Prf-mediated defences in the absence of AvrPto in tomato plants. Together, our results show that AvrPto derepresses host defences by interacting with the two defence-inhibition loops of Pto.

Background: Cas2 is universally conserved and essential for new CRISPR spacer acquisition. Results: Bha_Cas2 uses a single metal ion to cleave dsDNA and is likely activated by a pH-dependent conformational change. A method to classify Cas2 into ssRNase and dsDNase is proposed. Conclusion: B. halodurans and T. thermophilus Cas2 are metal-dependent endonucleases. Significance: dsDNase activity is consistent with the direct involvement of Cas2 in new spacer acquisition.

Human MRG15 is a transcription factor that plays a vital role in embryonic development, cell proliferation and cellular senescence. It comprises a putative chromo domain in the N-terminal part that has been shown to participate in chromatin remodeling and transcription regulation. We report here the crystal structure of human MRG15 chromo domain at 2.2 Å resolution. The MRG15 chromo domain consists of a β-barrel and a long α-helix and assumes a structure more similar to the Drosophila MOF chromo barrel domain than the typical HP1/Pc chromo domains. The β-barrel core contains a hydrophobic pocket formed by three conserved aromatic residues Tyr26, Tyr46 and Trp49 as a potential binding site for a modified residue of histone tail. However, the binding groove for the histone tail seen in the HP1/Pc chromo domains is pre-occupied by an extra β-strand. In vitro binding assay results indicate that the MRG15 chromo domain can bind to methylated Lys36, but not methylated Lys4, Lys9 and Lys27 of histone H3. These data together suggest that the MRG15 chromo domain may function as an adaptor module which can bind to a modified histone H3 in a mode different from that of the HP1/Pc chromo domains.