HO1 and PcyA proteins involved in phycobilin biosynthesis form a 1:2 complex with ferredoxin-1 required for photosynthesis

AbstractThe HO1 and PcyA genes, encoding heme oxygenase-1 (HO1) and phycocyanobilin (PCB):ferredoxin (Fd) oxidoreductase (PcyA), respectively, are required for chromophore synthesis in photosynthetic light-harvesting complexes, photoreceptors, and circadian clocks. In the PCB biosynthetic pathway, heme first undergoes cleavage to form biliverdin. I confirmed that Fd1 induced the formation of a stable and functional HO1 complex by the gel mobility shift assay. Furthermore, analysis by a chemical cross-linking technique designed to detect protein-protein interactions revealed that HO1 and PcyA directly interact with Fd in a 1:2 ratio. Thus, Fd1, a one-electron carrier protein in photosynthesis, drives the phycobilin biosynthetic pathway.Structured summaryMINT-7014657: Fd1 (uniprotkb:P0A3C9) and HO1 (uniprotkb:Q8DLW1) bind (MI:0407) by comigration in non-denaturing gel electrophoresis (MI:0404)MINT-7014666: HO1 (uniprotkb:Q8DLW1 and Fd1 (uniprotkb:P0A3C9) bind (MI:0407) by cross-linking studies (MI:0030)MINT-7014675: PcyA (uniprotkb:P59288) and Fd1 (uniprotkb:P0A3C9) bind (MI:0407) by cross-linking studies (MI:0030

Maximization of Learning Speed in the Motor Cortex Due to Neuronal Redundancy

Many redundancies play functional roles in motor control and motor learning. For example, kinematic and muscle redundancies contribute to stabilizing posture and impedance control, respectively. Another redundancy is the number of neurons themselves; there are overwhelmingly more neurons than muscles, and many combinations of neural activation can generate identical muscle activity. The functional roles of this neuronal redundancy remains unknown. Analysis of a redundant neural network model makes it possible to investigate these functional roles while varying the number of model neurons and holding constant the number of output units. Our analysis reveals that learning speed reaches its maximum value if and only if the model includes sufficient neuronal redundancy. This analytical result does not depend on whether the distribution of the preferred direction is uniform or a skewed bimodal, both of which have been reported in neurophysiological studies. Neuronal redundancy maximizes learning speed, even if the neural network model includes recurrent connections, a nonlinear activation function, or nonlinear muscle units. Furthermore, our results do not rely on the shape of the generalization function. The results of this study suggest that one of the functional roles of neuronal redundancy is to maximize learning speed

A Neural Correlate of Predicted and Actual Reward-Value Information in Monkey Pedunculopontine Tegmental and Dorsal Raphe Nucleus during Saccade Tasks

Dopamine, acetylcholine, and serotonin, the main modulators of the central nervous system, have been proposed to play important roles in the execution of movement, control of several forms of attentional behavior, and reinforcement learning. While the response pattern of midbrain dopaminergic neurons and its specific role in reinforcement learning have been revealed, the role of the other neuromodulators remains rather elusive. Here, we review our recent studies using extracellular recording from neurons in the pedunculopontine tegmental nucleus, where many cholinergic neurons exist, and the dorsal raphe nucleus, where many serotonergic neurons exist, while monkeys performed eye movement tasks to obtain different reward values. The firing patterns of these neurons are often tonic throughout the task period, while dopaminergic neurons exhibited a phasic activity pattern to the task event. The different modulation patterns, together with the activity of dopaminergic neurons, reveal dynamic information processing between these different neuromodulator systems

Cementoblastoma Arising in the Maxilla of an 8-Year-Old Boy: A Case Report

Cementoblastoma is an uncommon disease, representing only 1–8% of all odontogenic tumours. Furthermore, this tumour is especially uncommon in children, as only five cases have been reported in this age group. Here, we describe a case of cementoblastoma arising in the maxilla of an 8-year-old boy, that was treated with a partial maxillectomy. The patient's facial appearance has remained satisfactory, and the tumour has not recurred in the 9 years after the operation

Comparative analysis of right element mutant lox sites on recombination efficiency in embryonic stem cells

<p>Abstract</p> <p>Background</p> <p>Cre-mediated site-specific integrative recombination in mouse embryonic stem (ES) cells is a useful tool for genome engineering, allowing precise and repeated site-specific integration. To promote the integrative reaction, a left element/right element (LE/RE) mutant strategy using a pair of <it>lox </it>sites with mutations in the LE or RE of the <it>lox </it>sequence has previously been developed. Recombination between LE and RE mutant <it>lox </it>produces a wild-type <it>lox</it>P site as well as an LE+RE double mutant <it>lox </it>site, which has mutations in both sides and less affinity to Cre, resulting in stable integration. We previously demonstrated successful integrative recombination using <it>lox</it>71 (an LE mutant) and <it>lox</it>66 (an RE mutant) in ES cells. Recently, other LE/RE mutant <it>lox </it>sites showing higher recombination efficiency in <it>Escherichia coli </it>have been reported. However, their recombination efficiency in mammalian cells remains to be analyzed.</p> <p>Results</p> <p>Using ES cells, we compared six RE mutant <it>lox </it>sites, focusing on their recombination efficiency with <it>lox</it>71. All of the RE mutant <it>lox </it>sites showed similar recombination efficiency. We then analyzed the stability of the recombined product, i.e., the LE+RE double mutant <it>lox </it>site, under continuous and strong Cre activity in ES cells. Two RE mutants, <it>lox</it>JTZ17 and <it>lox</it>KR3, produced more stable LE+RE double mutant <it>lox </it>than did the <it>lox</it>66/71 double mutant.</p> <p>Conclusion</p> <p>The two mutant RE <it>lox </it>sites, <it>lox</it>JTZ17 and <it>lox</it>KR3, are more suitable than <it>lox</it>66 for Cre-mediated integration or inversion in ES cells.</p