Fission yeast TOR signaling is essential for the down-regulation of a hyperactivated stress-response MAP kinase under salt stress

TOR (target of rapamycin) signaling regulates cell growth and division in response to environmental stimuli such as the availability of nutrients and various forms of stress. The vegetative growth of fission yeast cells, unlike other eukaryotic cells, is not inhibited by treatment with rapamycin. We found that certain mutations including pmc1Δ (Ca²⁺-ATPase), cps9-193 (small GTPase, Ryh1) and cps1-12 (1,3-β-d-glucan synthase, Bgs1) confer a rapamycin-sensitive phenotype to cells under salt stress with potassium chloride (>0.5 M). Cytometric analysis revealed that the mutant cells were unable to enter the mitotic cell cycle when treated with the drug under salt stress. Gene cloning and overexpression experiments revealed that the sensitivity to rapamycin was suppressed by the ectopic expression of tyrosine phosphatases, Pyp1 and Pyp2, which are negative regulators of Spc1/Sty1 mitogen-activated protein kinase (MAPK). The level of tyrosine phosphorylation on Spc1 was higher and sustained substantially longer in these mutants than in the wild type under salt stress. The hyperphosphorylation was significantly suppressed by overexpression of pyp1 ⁺ with concomitant resumption of the mutant cells’ growth. In fission yeast, TOR signaling has been thought to stimulate the stress-response pathway, because mutations of TORC2 components such as Tor1, Sin1 and Ste20 result in similar sensitive phenotypes to environmental stress. The present study, however, strongly suggests that TOR signaling is required for the down-regulation of a hyperactivated Spc1 for reentry into the mitotic cell cycle. This finding may shed light on our understanding of a new stress-responsive mechanism in TOR signaling in higher organisms.     

Receptor-like cytoplasmic kinases are pivotal components in pattern recognition receptor-mediated signaling in plant immunity

Innate immunity is generally initiated with recognition of conserved pathogen-associated molecular patterns (PAMPs). PAMPs are perceived by pattern recognition receptors (PRRs), leading to activation of a series of immune responses, including the expression of defense genes, ROS production and activation of MAP kinase. Recent progress has indicated that receptor-like cytoplasmic kinases (RLCKs) are directly activated by ligand- activated PRRs and initiate pattern -triggered immunity (PTI) in both Arabidopsis and rice. To suppress PTI, pathogens inhibit the RLCKs by many types of effectors, including AvrAC, AvrPphB and Xoo1488. In this review, we summarize recent advances in RLCK-mediated PTI in plants.     

A 5-bp Insertion in Mip Causes Recessive Congenital Cataract in KFRS4/Kyo Rats

We discovered a new cataract mutation, kfrs4, in the Kyoto Fancy Rat Stock (KFRS) background. Within 1 month of birth, all kfrs4/kfrs4 homozygotes developed cataracts, with severe opacity in the nuclei of the lens. In contrast, no opacity was observed in the kfrs4/+ heterozygotes. We continued to observe these rats until they reached 1 year of age and found that cataractogenesis did not occur in kfrs4/+ rats. To define the histological defects in the lenses of kfrs4 rats, sections of the eyes of these rats were prepared. Although the lenses of kfrs4/kfrs4 homozygotes showed severely disorganised fibres and vacuolation, the lenses of kfrs4/+ heterozygotes appeared normal and similar to those of wild-type rats. We used positional cloning to identify the kfrs4 mutation. The mutation was mapped to an approximately 9.7-Mb region on chromosome 7, which contains the Mip gene. This gene is responsible for a dominant form of cataract in humans and mice. Sequence analysis of the mutant-derived Mip gene identified a 5-bp insertion. This insertion is predicted to inactivate the MIP protein, as it produces a frameshift that results in the synthesis of 6 novel amino acid residues and a truncated protein that lacks 136 amino acids in the C-terminal region, and no MIP immunoreactivity was observed in the lens fibre cells of kfrs4/kfrs4 homozygous rats using an antibody that recognises the C- and N-terminus of MIP. In addition, the kfrs4/+ heterozygotes showed reduced expression of Mip mRNA and MIP protein and the kfrs4/kfrs4 homozygotes showed no expression in the lens. These results indicate that the kfrs4 mutation conveys a loss-of-function, which leads to functional inactivation though the degradation of Mip mRNA by an mRNA decay mechanism. Therefore, the kfrs4 rat represents the first characterised rat model with a recessive mutation in the Mip gene.     

Binding of Polysaccharide to Peptidoglycan in Cell Wall of Streptomyces roseochromogenes

The polysaccharide-peptidoglycan complex, which was prepared with lysozyme from Streptomyces roseochromogenes IAM53 cell walls, was hydrolyzed with lytic enzyme of Flavo-bacterium to separate polysaccharide. The enzymatically prepared polysaccharide (100 mg) contained 500 μmoles of hexoses, 40 μmoles of hexosamines and 31 μmoles of phosphate. Hexoses consisted of mannose and galactose in a molar ratio of 5 to 1. Hexosamines consisted of equimolar glucosamine and muramic acid, a half of which was identified as muramic acid 6-phosphate. The reducing end of the polysaccharide was muramic acid. The polysaccharide extracted with trichloroacetic acid contained no muramic acid-phosphate. So the polysaccharide moiety of S. roseochromogenes cell walls must be linked covalently to 6-position of muramic acid in peptidoglycan through phosphate,     

Advantages of genome sequencing by long-read sequencer using SMRT technology in medical area

PacBio RS II is the first commercialized third-generation DNA sequencer able to sequence a single molecule DNA in real-time without amplification. PacBio RS II’s sequencing technology is novel and unique, enabling the direct observation of DNA synthesis by DNA polymerase. PacBio RS II confers four major advantages compared to other sequencing technologies: long read lengths, high consensus accuracy, a low degree of bias, and simultaneous capability of epigenetic characterization. These advantages surmount the obstacle of sequencing genomic regions such as high/low G+C, tandem repeat, and interspersed repeat regions. Moreover, PacBio RS II is ideal for whole genome sequencing, targeted sequencing, complex population analysis, RNA sequencing, and epigenetics characterization. With PacBio RS II, we have sequenced and analyzed the genomes of many species, from viruses to humans. Herein, we summarize and review some of our key genome sequencing projects, including full-length viral sequencing, complete bacterial genome and almost-complete plant genome assemblies, and long amplicon sequencing of a disease-associated gene region. We believe that PacBio RS II is not only an effective tool for use in the basic biological sciences but also in the medical/clinical setting.     

Comparative analysis of mineralocorticoid receptor expression among vocal learners (Bengalese finch and budgerigar) and non-vocal learners (quail and ring dove) has implications for the evolution of avian vocal learning

Mineralocorticoid receptor is the receptor for corticosteroids such as corticosterone or aldosterone. Previously, we found that mineralocorticoid receptor was highly expressed in song nuclei of a songbird, Bengalese finch (Lonchura striata var. domestica). Here, to examine the relationship between mineralocorticoid receptor expression and avian vocal learning, we analyzed mineralocorticoid receptor expression in the developing brain of another vocal learner, budgerigar (Melopsittacus undulatus) and non-vocal learners, quail (Coturnix japonica) and ring dove (Streptopelia capicola). Mineralocorticoid receptor showed vocal control area-related expressions in budgerigars as Bengalese finches, whereas no such mineralocorticoid receptor expressions were seen in the telencephalon of non-vocal learners. Thus, these results suggest the possibility that mineralocorticoid receptor plays a role in vocal development of parrots as songbirds and that the acquisition of mineralocorticoid receptor expression is involved in the evolution of avian vocal learning.     

Mate preference in males of the cabbage butterfly, Pieris rapae crucivora, changes seasonally with the change in female UV color

We initially investigated whether females of the cabbage butterfly, Pieris rapae crucivora, exhibit a seasonal change in ultraviolet wing color, which is a key stimulus for mate recognition by conspecific males, and whether and how a seasonal change affects the mating behavior of the males. We found that female UV wing color changes seasonally, the color being more pronounced in summer than in spring or autumn. We also demonstrated that male mate preference changes seasonally, concomitantly with the change in female UV color. Specifically, males appearing in summer exhibit a mating preference for summer-form females over spring- or autumn-form females, while those appearing in spring or autumn exhibit no seasonal preference, thereby facilitating more effective mate location. Our results suggest that this field of study will require more strictly controlled experimental investigation in which the seasonal change in UV color is considered when UV-influenced mating behaviors such as mate choice are investigated.     

Chromosome-scale genome assembly of the transformation-amenable common wheat cultivar ‘Fielder’

We have established a high-quality, chromosome-level genome assembly for the hexaploid common wheat cultivar ‘Fielder’, an American, soft, white, pastry-type wheat released in 1974 and known for its amenability to Agrobacterium tumefaciens-mediated transformation and genome editing. Accurate, long-read sequences were obtained using PacBio circular consensus sequencing with the HiFi approach. Sequence reads from 16 SMRT cells assembled using the hifiasm assembler produced assemblies with N50 greater than 20 Mb. We used the Omni-C chromosome conformation capture technique to order contigs into chromosome-level assemblies, resulting in 21 pseudomolecules with a cumulative size of 14.7 and 0.3 Gb of unanchored contigs. Mapping of published short reads from a transgenic wheat plant with an edited seed-dormancy gene, TaQsd1, identified four positions of transgene insertion into wheat chromosomes. Detection of guide RNA sequences in pseudomolecules provided candidates for off-target mutation induction. These results demonstrate the efficiency of chromosome-scale assembly using PacBio HiFi reads and their application in wheat genome-editing studies.