MicroRNAs (miRNAs) are regulators of gene expression in plants and animals. The biogenesis of miRNAs is precisely controlled to secure normal development of organisms. Here we report that TOUGH (TGH) is a component of the DCL1-HYL1-SERRATE complex that processes primary transcripts of miRNAs [i.e., primary miRNAs (pri-miRNAs)] into miRNAs in Arabidopsis. Lack of TGH impairs multiple DCL activities in vitro and reduces the accumulation of miRNAs and siRNAs in vivo. TGH is an RNA-binding protein, binds pri-miRNAs and precursor miRNAs in vivo, and contributes to pri-miRNA-HYL1 interaction. These results indicate that TGH might regulate abundance of miRNAs through promoting DCL1 cleavage efficiency and/or recruitment of pri-miRNAs.S mall RNAs, including microRNAs (miRNAs) and siRNAs, are sequence-specific regulators of gene expression in plants and animals (1). miRNAs are derived from imperfect stem-loop transcripts, called primary miRNAs (pri-miRNAs), which are predominately produced by DNA-dependent RNA polymerase II, whereas siRNAs are processed from perfect or near-perfect long dsRNAs (2). After generation, miRNA and siRNA are loaded into an RNA-induced silencing complex containing the Argonaute protein to guide posttranscriptional or transcriptional gene silencing (1).In animals, pri-miRNAs are first processed to precursor miRNAs (pre-miRNAs) in the nucleus by the microprocessor containing Drosha and a dsRNA-binding protein DGCR8 (1). The resulting pre-miRNAs are then processed by Dicer in the cytoplasm to produce mature miRNAs (1). It has emerged that the activities of Drosha and Dicer are controlled to regulate miRNA expression in response to developmental and environmental signals (3). In Arabidopsis, DCL1, a dsRNA-binding protein, HYL1, and a zinc finger protein, SERRATE (SE), form a complex to process pri-miRNAs in the nucleus to pre-miRNAs and then to mature miRNAs (4-6). The accumulation of miRNAs in Arabidopsis also requires DDL, which was proposed to stabilize pri-miRNAs and to facilitate their processing (7). Recently, two cap-binding proteins, CBP80/ABH1 and CBP20, were found to be required for pre-mRNA splicing and primiRNA processing (8, 9). Plants also encode several classes of endogenous siRNAs, including the natural antisense transcriptderived siRNA, siRNA derived from repetitive DNA sequences (rasiRNA), and transacting siRNA (ta-siRNA) (10). In Arabidopsis, the generation of these siRNAs from long dsRNAs involves DCL1 homologues DCL2, DCL3, and DCL4, which produce 22-nt, 24-nt, and 21-nt siRNAs, respectively (11-13).In this report, we show that TOUGH (TGH) is an important factor for miRNA and siRNA biogenesis. Loss-of-function TGH in tgh-1 reduces the activity of multiple DCLs in vitro and the accumulation of miRNA and siRNAs in vivo. In the miRNA pathway, TGH associates with the DCL1 complex and binds primiRNAs and pre-miRNAs. TGH is required for the efficient in vivo interaction between pri-miRNA and HYL1. These data suggest that TGH assists DCLs to efficiently process and/or recruit the prec...

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) was completed with its main structure installed on September 25, 2016, after which it entered the commissioning phase. This paper aims to introduce the commissioning progress of the FAST over the past two years. To improve its operational reliability and ensure effective observation time, FAST has been equipped with a real-time information system for the active reflector system and hierarchical commissioning scheme for the feed support system, which ultimately achieves safe operation of the two systems. For meeting the high-performance indices, a high-precision measurement system was set up based on the effective control methods that were implemented for the active reflector system and feed support system. Since the commissioning of the FAST, a low-frequency ultra-wideband receiver and 19-beam 1.05-1.45 GHz receiver have been mainly used. Telescope efficiency, pointing accuracy, and system noise temperature were completely tested and ultimately achieved the acceptance indices of the telescope. The FAST has been in the process of national acceptance preparations and has begun to search for pulsars. In the future, it will still strive to improve its capabilities and expand its application prospects. Keywords: Radio telescopes and instrumentation, astronomical observations, radio wave receivers, algorithms and implementation, control systems 95.55.Jz; 95.85.-e; 07.57.Kp; 07.05.Kf; 07.05.Dz Till date, several observation modes, such as tracking, drift scanning, andbasketweave scanning, have been realized, which means that the functional commissioning tasks have been completed. Now, the sensitivity of the FAST has reached 2,000 m 2 /K, the system noise temperature has been controlled below 20 K (19-beam 1.05-1.45 GHz receiver), and the pointing accuracy of the feed receivers has reached about 16″. The FAST has already begun to search for pulsars in batches.Several researches based on the FAST telescope have been reported. Qian et al. [3] reported their observation and basic parameters of the first pulsar discovered by the FAST, PSR J1900−0134. Zhang et al. [4] used FAST parameters obtained from the commissioning data to estimate the sensitivity of the CRAFTS extragalactic HI survey and predict its survey capacity in the future. Yu et al. [5] observed the abnormal emission shift event of PSR B0919+06 using the FAST with the ultra-wideband receive system. They found the potential existence of a slow-drifting mode between two major abnormal events. A sequence of dimmed pulses was observed during one of those events at all frequency bands. Lu, Peng et al. [6] reported the analysis of three rotating radio transients (RRATs), namely J1538+2345, J1854+0306, and J1913+1330, observed using the FAST. The derived burst rates of the three RRATs are higher than previous results owing to the high sensitivity of the FAST. Lu et al. [7] showed both the mean and single pulses of PSR B2016+28, observed in detail using the FAST. Wang, Zhu, Guo, et al. [8] developed a pulsa...

Schwann cells (SCs) have been shown to be a key element in promoting axonal regeneration after being grafted into the central nervous system (CNS). In the present study, SC-supported axonal regrowth was tested in an adult rat spinal cord implantation model. This model is characterized by a right spinal cord hemisection at the eighth thoracic segment, implantation of a SC-containing mini-channel and restoration of cerebrospinal fluid circulation by suturing the dura. We demonstrate that a tissue cable containing grafted SCs formed an effective bridge between the two stumps of the hemicord 1 month after transplantation. Approximately 10 000 myelinated and unmyelinated axons (1 : 9) per cable were found at its midpoint. In addition to propriospinal axons and axons of peripheral nervous system (PNS) origin, axons from as many as 19 brainstem regions also grew into the graft without additional treatments. Most significantly, some regenerating axons in the SC grafts were able to penetrate through the distal graft-host interface to re-enter the host environment, as demonstrated by anterograde axonal labelling. These axons coursed toward, and then entered the grey matter where terminal bouton-like structures were observed. In channels containing no SCs, limited axonal growth was seen within the graft and no axons penetrated the distal interface. These findings further support the notion that SCs are strong promotors of axonal regeneration and that the mini-channel model may be appropriate for further investigation of axonal re-entry, synaptic reconnection and functional recovery following spinal cord injury.

CDC5 is a MYB-related protein that exists in plants, animals, and fungi. In Arabidopsis, CDC5 regulates both growth and immunity through unknown mechanisms. Here, we show that CDC5 from Arabidopsis positively regulates the accumulation of microRNAs (miRNAs), which control many biological processes including development and adaptations to environments in plants. CDC5 interacts with both the promoters of genes encoding miRNAs (MIR) and the DNA-dependent RNA polymerase II. As a consequence, lack of CDC5 reduces the occupancy of polymerase II at MIR promoters, as well as MIR promoter activities. In addition, CDC5 is associated with the DICER-LIKE1 complex, which generates miRNAs from their primary transcripts and is required for efficient miRNA production. These results suggest that CDC5 may have dual roles in miRNA biogenesis: functioning as a positive transcription factor of MIR and/or acting as a component of the DICER-LIKE1 complex to enhance primary miRNA processing.M icroRNAs (miRNAs) and small interfering RNAs (siRNAs) are ∼22-nucleotide (nt) noncoding RNAs that regulate various biological processes including development, metabolism, and immunity in plants and animals (1-3). miRNAs are generated from primary miRNA transcripts (pri-miRNAs) containing stem-loop structure, whereas siRNAs are derived from long, perfect, doublestranded RNAs (dsRNAs) (1-3). They are associated with members of the Argonaute protein family to repress gene expression at posttranscriptional and/or transcriptional levels (1-3). In addition to miRNAs, plants encode two major classes of siRNAs: siRNAs derived from repeated DNAs (ra-siRNAs) and transacting siRNAs (ta-siRNAs) (4-6).Studies in Arabidopsis have established the framework of miRNA biogenesis in plants (1-3). In Arabidopsis, pri-miRNAs are primarily transcribed by DNA-dependent RNA polymerase II (Pol II), with assistance from the mediator complex and the transcription factor Negative on TATA less2 (NOT2) (7,8). After transcription, pri-miRNAs are processed by an RNase III enzyme called DICER-LIKE1 (DCL1) to miRNA precursors and then to mature miRNAs (9, 10). The efficient processing of pri-miRNA requires SERRATE (SE; a zinc finger protein), TOUGH (an RNA-binding protein), and a dephosphorylated HYPONASTIC LEAVES1 (HYL1; a double-stranded RNA binding protein) that form a complex with DCL1 (11-18). SE and HYL1 also promote the processing accuracy of pri-miRNAs (19). Four other proteins, DAWDLE (DDL; an RNA binding protein), Cap-binding protein 20, Cap-binding protein 80, and NOT2, which are associated with the DCL1 complex (8,(20)(21)(22), also function in miRNA biogenesis. Recent studies also reveal that the correct localization of DCL1 requires NOT2 and MODIFIER OF SNC1, 2 (an RNA binding protein) (8,23). In addition, the accumulation of a subset of miRNAs requires a proline-rich protein named SICKLE (24).The cell division cycle 5 (CDC5) protein is a conserved protein in animals, plants, and fungi (25). It was first isolated from Schizosaccharomyces pombe as a cell cycle regulat...