Acetylation regulates monopolar attachment at multiple levels during meiosis I in fission yeast

In fission yeast, meiotic mono-orientation of sister kinetochores is established by cohesion at the core centromere, which is established by a meiotic cohesin complex and the kinetochore protein Moa1. The cohesin subunit Psm3 is acetylated by Eso1 and deacetylated by Clr6. We show that in meiosis, Eso1 is required for establishing core centromere cohesion during S phase, whereas Moa1 is required for maintaining this cohesion after S phase. The clr6-1 mutation suppresses the mono-orientation defect of moa1Δ cells, although the Clr6 target for this suppression is not Psm3. Thus, several acetylations are crucial for establishing and maintaining core centromere cohesion.     

Binding and Functional Properties of Five Extrinsic Proteins in Oxygen-evolving Photosystem II from a Marine Centric Diatom,Chaetoceros gracilis

Oxygen-evolving photosystem II (PSII) isolated from a marine centric diatom, Chaetoceros gracilis, contains a novel extrinsic protein (Psb31) in addition to four red algal type extrinsic proteins of PsbO, PsbQ′, PsbV, and PsbU. In this study, the five extrinsic proteins were purified from alkaline Tris extracts of the diatom PSII by anion and cation exchange chromatographic columns at different pH values. Reconstitution experiments in various combinations with the purified extrinsic proteins showed that PsbO, PsbQ′, and Psb31 rebound directly to PSII in the absence of other extrinsic proteins, indicating that these extrinsic proteins have their own binding sites in PSII intrinsic proteins. On the other hand, PsbV and PsbU scarcely rebound to PSII alone, and their effective bindings required the presence of all of the other extrinsic proteins. Interestingly, PSII reconstituted with Psb31 alone considerably restored the oxygen evolving activity in the absence of PsbO, indicating that Psb31 serves as a substitute in part for PsbO in supporting oxygen evolution. A significant difference found between PSIIs reconstituted with Psb31 and with PsbO is that the oxygen evolving activity of the former is scarcely stimulated by Cl⁻ and Ca²⁺ ions but that of the latter is largely stimulated by these ions, although rebinding of PsbV and PsbU activated oxygen evolution in the absence of Cl⁻ and Ca²⁺ ions in both the former and latter PSIIs. Based on these results, we proposed a model for the association of the five extrinsic proteins with intrinsic proteins in diatom PSII and compared it with those in PSIIs from the other organisms.     

Application of a new probabilistic model for recognizing complex patterns in glycans

MOTIVATION: The study of carbohydrate sugar chains, or glycans, has been one of slow progress mainly due to the difficulty in establishing standard methods for analyzing their structures and biosynthesis. Glycans are generally tree structures that are more complex than linear DNA or protein sequences, and evidence shows that patterns in glycans may be present that spread across siblings and into further regions that are not limited by the edges in the actual tree structure itself. Current models were not able to capture such patterns. RESULTS: We have applied a new probabilistic model, called probabilistic sibling-dependent tree Markov model (PSTMM), which is able to inherently capture such complex patterns of glycans. Not only is the ability to capture such patterns important in itself, but this also implies that PSTMM is capable of performing multiple tree structure alignments efficiently. We prove through experimentation on actual glycan data that this new model is extremely useful for gaining insight into the hidden, complex patterns of glycans, which are so crucial for the development and functioning of higher level organisms. Furthermore, we also show that this model can be additionally utilized as an innovative approach to multiple tree alignment, which has not been applied to glycan chains before. This extension on the usage of PSTMM may be a major step forward for not only the structural analysis of glycans, but it may consequently prove useful for discovering clues into their function.     

Swapping of the beta-hairpin region between Sp1 and GLI zinc fingers: significant role of the beta-hairpin region in DNA binding properties of C2H2-type zinc finger peptides

The recent design strategy of zinc finger peptides has mainly focused on the alpha-helix region, which plays a direct role in DNA recognition. On the other hand, the study of non-DNA-contacting regions is extremely scarce. By swapping the beta-hairpin regions between the Sp1 and GLI zinc fingers, in this study, we investigated how the beta-hairpin region of the C(2)H(2)-type zinc finger peptides contributes to the DNA binding properties. Surprisingly, the Sp1 mutant with the GLI-type beta-hairpin had a higher DNA binding affinity than that of the wild-type Sp1. The result of the DNase I footprinting analyses also showed the change in the DNA binding pattern. In contrast, the GLI zinc finger completely lost DNA binding ability as a result of exchanging the beta-hairpin region. These results strongly indicate that the beta-hairpin region appears to function as a scaffold and has an important effect on the DNA binding properties of the C(2)H(2)-type zinc finger peptides.     

Spinal Cord Stimulation Exerts Neuroprotective Effects against Experimental Parkinson’s Disease

In clinical practice, deep brain stimulation (DBS) is effective for treatment of motor symptoms in Parkinson’s disease (PD). However, the mechanisms have not been understood completely. There are some reports that electrical stimulation exerts neuroprotective effects on the central nervous system diseases including cerebral ischemia, head trauma, epilepsy and PD, although there are a few reports on neuroprotective effects of spinal cord stimulation (SCS). We investigated the neuroprotective effects of high cervical SCS on PD model of rats. Adult female Sprague-Dawley rats received hour-long SCS (2, 50 or 200 Hz) with an epidural electrode at C1–2 level for 16 consecutive days. At 2 days after initial SCS, 6-hydroxydopamine (6-OHDA) was injected into the right striatum of rats. Behavioral evaluations of PD symptoms were employed, including cylinder test and amphetamine-induced rotation test performed at 1 and 2 weeks after 6-OHDA injection. Animals were subsequently euthanized for immunohistochemical investigations. In order to explore neurotrophic and growth factor upregulation induced by SCS, another cohort of rats that received 50 Hz SCS was euthanized at 1 and 2 weeks after lesion for protein assays. Behavioral tests revealed that the number of amphetamine-induced rotations decreased in SCS groups. Immunohistochemically, tyrosine hydroxylase (TH)-positive fibers in the striatum were significantly preserved in SCS groups. TH-positive neurons in the substantia nigra pars compacta were significantly preserved in 50 Hz SCS group. The level of vascular endothelial growth factor (VEGF) was upregulated by SCS at 1 week after the lesion. These results suggest that high cervical SCS exerts neuroprotection in PD model of rats, at least partially by upregulation of VEGF. SCS is supposed to suppress or delay PD progression and might become a less invasive option for PD patients, although further preclinical and clinical investigations are needed to confirm the effectiveness and safety.     

Improvement in spermatogenic function after subcutaneous implantation of a capsule containing an aromatase inhibitor in four oligozoospermic dogs and one azoospermic dog with high plasma estradiol-17beta concentrations

A capsule containing an aromatase inhibitor (4-androsten-4-ol-3,17-dione) was subcutaneously implanted in four oligozoospermic beagle dogs and one azoospermic beagle dog with high plasma estradiol-17beta (E2) concentrations (15-19 pg/ml) and low plasma testosterone (T) concentrations (0.6-0.8 ng/ml) for 8 weeks and the effect of the aromatase inhibitor on spermatogenic dysfunction was assessed. Plasma E2 and T concentrations and semen quality were examined at 1 week intervals from 3 weeks before to 12 weeks after the start of treatment. Testicular biopsies were done twice (capsule implantation and removal). Plasma E2 concentrations of all dogs decreased (9-14 pg/ml) and plasma T concentrations increased (2.0-2.6 ng/ml) from 3 weeks after capsule implantation to capsule removal. The mean number of spermatozoa ejaculated by all four oligozoospermic dogs between 4 and 9 weeks after implantation was higher (127 x 10(6) to 205 x 10(6)) than before implantation (20 x 10(6) to 38 x 10(6)) (P < 0.05 and 0.01). Very low numbers (2 x 10(4) to 4 x 10(4)) of immotile spermatozoa were observed between 7 and 8 weeks after implantation in the semen collected from the dog with azoospermia. Before implantation, a few spermatozoa were seen in only one-fifth of the seminiferous tubules in this dog; 8 weeks after implantation, the mean diameter and mean number of round spermatids in the seminiferous tubules in all five dogs were higher than before implantation (P < 0.05). Implantation of the capsule containing the aromatase inhibitor in infertile dogs with abnormally high plasma E2 concentrations improved their spermatogenic function, concurrent with decreased plasma E2 and increased plasma T.