The DWF4 gene of Arabidopsis encodes a cytochrome P450 that mediates multiple 22alpha-hydroxylation steps in brassinosteroid biosynthesis.

dwarf4 (dwf4) mutants of Arabidopsis display a dwarfed phenotype due to a lack of cell elongation. Dwarfism could be rescued by the application of brassinolide, suggesting that DWF4 plays a role in brassinosteroid (BR) biosynthesis. The DWF4 locus is defined by four mutant alleles. One of these is the result of a T-DNA insertion. Plant DNA flanking the insertion site was cloned and used as a probe to isolate the entire DWF4 gene. Sequence analysis revealed that DWF4 encodes a cytochrome P450 monooxygenase with 43% identity to the putative Arabidopsis steroid hydroxylating enzyme CONSTITUTIVE PHOTOMORPHOGENESIS AND DWARFISM. Sequence analysis of two other mutant alleles revealed deletions or a premature stop codon, confirming that DWF4 had been cloned. This sequence similarity suggests that DWF4 functions in specific hydroxylation steps during BR biosynthesis. In fact, feeding studies utilizing BR intermediates showed that only 22alpha-hydroxylated BRs rescued the dwf4 phenotype, confirming that DWF4 acts as a 22alpha-hydroxylase.     

Viewing Complex,Dynamic Scenes “Through the Eyes” of Another Person: The Gaze-Replay Paradigm

We present a novel “Gaze-Replay” paradigm that allows the experimenter to directly test how particular patterns of visual input—generated from people’s actual gaze patterns—influence the interpretation of the visual scene. Although this paradigm can potentially be applied across domains, here we applied it specifically to social comprehension. Participants viewed complex, dynamic scenes through a small window displaying only the foveal gaze pattern of a gaze “donor.” This was intended to simulate the donor’s visual selection, such that a participant could effectively view scenes “through the eyes” of another person. Throughout the presentation of scenes presented in this manner, participants completed a social comprehension task, assessing their abilities to recognize complex emotions. The primary aim of the study was to assess the viability of this novel approach by examining whether these Gaze-Replay windowed stimuli contain sufficient and meaningful social information for the viewer to complete this social perceptual and cognitive task. The results of the study suggested this to be the case; participants performed better in the Gaze-Replay condition compared to a temporally disrupted control condition, and compared to when they were provided with no visual input. This approach has great future potential for the exploration of experimental questions aiming to unpack the relationship between visual selection, perception, and cognition.     

p53 negatively regulates Pin1 expression under ER stress

Accumulating evidence suggests that endoplasmic reticulum (ER) stress plays a major role in the development of many diseases. A previous study indicated that the apoptotic regulator p53 is significantly increased in response to ER stress and participates in ER stress-induced apoptosis. However, the regulators of p53 expression during ER stress are still not fully understood. Here, we investigated whether p53 contributes to the impairment of Pin1 signaling under ER stress. We found that treatment with thapsigargin, a stimulator of p53 expression and an inducer of ER stress, decreased Pin1 expression in HCT116 cells. Also, we identified functional p53 response elements (p53REs) in the Pin1 promoter. Overexpression of p53 significantly decreased Pin1 expression in HCT116 cells while abolition of p53 gene expression induced Pin1 expression. Pin1 expression was significantly increased by treatment with the p53 inhibitor pifithrin-α or down-regulation of p53 expression. Taken together, ER stress decreased Pin1 expression through p53 activation, and this mechanism may be associated with ER stress-induced cell death. These data reported here support the importance of Pin1 as a potential target molecule mediating tumor development.     

CaMKIIα interacts with M4 muscarinic receptors to control receptor and psychomotor function

Muscarinic acetylcholine receptors (mAChRs) are widely expressed in the mammalian brain and are essential for neuronal functions. These receptors are believed to be actively regulated by intracellular signals, although the underlying mechanisms are largely unknown. In this study, we show that Ca²⁺/calmodulin‐dependent protein kinase II (CaMKII) binds directly and selectively to one of five mAChR subtypes, M4 receptors (M4Rs), at their C‐terminal regions of second intracellular loops. This binding relies on Ca²⁺ activation of the kinase and leads to the phosphorylation of M4Rs at a specific threonine site (Thr145). Complementary in vivo studies in rat striatal neurons enriched with M4Rs confirm that rising Ca²⁺ recruits CaMKIIα to M4Rs to potentiate receptor signalling, which controls behavioural sensitivity to dopamine stimulation in an activity‐dependent manner. Our data identify a new model of protein–protein interactions. In a Ca²⁺‐sensitive manner, CaMKIIα regulates M4R efficacy and controls the acetylcholine–dopamine balance in the basal ganglia and also the dynamics of movement.     

T-DNA tagged knockout mutation of rice <Emphasis Type="Italic">OsGSK1</Emphasis>, an orthologue of <Emphasis Type="Italic">Arabidopsis BIN2</Emphasis>, with enhanced tolerance to various abiotic stresses

T-DNA-tagged rice plants were screened under cold- or salt-stress conditions to determine the genes involved in the molecular mechanism for their abiotic-stress response. Line 0-165-65 was identified as a salt-responsive line. The gene responsible for this GUS-positive phenotype was revealed by inverse PCR as OsGSK1 (O ryza s ativa g lycogen s ynthase k inase3-like gene 1), a member of the plant GSK3/SHAGGY-like protein kinase genes and an orthologue of the Arabidopsis b rassinosteroid in sensitive 2 (BIN2), AtSK21. Northern blot analysis showed that OsGSK1 was most highly detected in the developing panicles, suggesting that its expression is developmental stage specific. Knockout (KO) mutants of OsGSK1 showed enhanced tolerance to cold, heat, salt, and drought stresses when compared with non-transgenic segregants (NT). Overexpression of the full-length OsGSK1 led to a stunted growth phenotype similar to the one observed with the gain-of-function BIN/AtSK21 mutant. This suggests that OsGSK1 might be a functional rice orthologue that serves as a negative regulator of brassinosteroid (BR)-signaling. Therefore, we propose that stress-responsive OsGSK1 may have physiological roles in stress signal-transduction pathways and floral developmental processes. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Serry Koh and Sang-Choon Lee are co-first authors.     

A Ds-insertion mutant of OSH6 (Oryza sativa Homeobox 6) exhibits outgrowth of vestigial leaf-like structures, bracts, in rice

OSH6 (Oryza sativa Homeobox6) is an ortholog of lg3 (Liguleless3) in maize. We generated a novel allele, termed OSH6-Ds, by inserting a defective Ds element into the third exon of OSH6, which resulted in a truncated OSH6 mRNA. The truncated mRNA was expressed ectopically in leaf tissues and encoded the N-terminal region of OSH6, which includes the KNOX1 and partial KNOX2 subdomains. This recessive mutant showed outgrowth of bracts or produced leaves at the basal node of the panicle. These phenotypes distinguished it from the OSH6 transgene whose ectopic expression led to a “blade to sheath transformation” phenotype at the midrib region of leaves, similar to that seen in dominant Lg3 mutants. Expression of a similar truncated OSH6 cDNA from the 35S promoter (35S::ΔOSH6) confirmed that the ectopic expression of this product was responsible for the aberrant bract development. These data suggest that OSH6-Ds interferes with a developmental mechanism involved in bract differentiation, especially at the basal nodes of panicles. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.