Structural basis for corepressor assembly by the orphan nuclear receptor TLX.

The orphan nuclear receptor TLX regulates neural stem cell self-renewal in the adult brain and functions primarily as a transcription repressor through recruitment of Atrophin corepressors, which bind to TLX via a conserved peptide motif termed the Atro box. Here we report crystal structures of the human and insect TLX ligand-binding domain in complex with Atro box peptides. In these structures, TLX adopts an autorepressed conformation in which its helix H12 occupies the coactivator-binding groove. Unexpectedly, H12 in this autorepressed conformation forms a novel binding pocket with residues from helix H3 that accommodates a short helix formed by the conserved ALXXLXXY motif of the Atro box. Mutations that weaken the TLX-Atrophin interaction compromise the repressive activity of TLX, demonstrating that this interaction is required for Atrophin to confer repressor activity to TLX. Moreover, the autorepressed conformation is conserved in the repressor class of orphan nuclear receptors, and mutations of corresponding residues in other members of this class of receptors diminish their repressor activities. Together, our results establish the functional conservation of the autorepressed conformation and define a key sequence motif in the Atro box that is essential for TLX-mediated repression.

Ataxin-1 and Brother of ataxin-1 are components of the Notch signalling pathway.

Ataxin-1 (ATXN1), a causative factor for spinocerebellar ataxia type 1 (SCA1), and the related Brother of ATXN1 (BOAT1) are human proteins involved in transcriptional repression. So far, little is known about which transcriptional pathways mediate the effects of ATXN1 and BOAT1. From our analyses of the properties of BOAT1 in Drosophila and of both proteins in mammalian cells, we report here that BOAT1 and ATXN1 are components of the Notch signalling pathway. In Drosophila, BOAT1 compromises the activities of Notch. In mammalian cells, both ATXN1 and BOAT1 bind to the promoter region of Hey1 and inhibit the transcriptional output of Notch through direct interactions with CBF1, a transcription factor that is crucial for the Notch pathway. Our results suggest that, in addition to their involvement in SCA1, ATXN1 and BOAT1 might participate in several Notch-controlled developmental and pathological processes.

Applications of mobile learning on college students' water leisure sports in the post-pandemic era.

This study explored the relationship and influence of college students' participation in water leisure sports, as well as the technology acceptance model (TAM). With the rapid development of the economy, the government is promoting various water leisure sports centered on the concept and policy of a maritime- and ocean-based nation. Based on the TAM, this study investigated the relationships among its ease of use, usefulness, water leisure involvement, benefits, barriers, and intentions to participate in water activities in connection with college students participating in water leisure sports. A total of 420 college students who participated in water leisure activities were sampled. There were 370 valid questionnaires, and the recovery rate of valid questionnaires was 82.2%. The data were analyzed by the structural equation modeling of the partial least squares method (PLS-SEM). The results show that the ease of use of water facilities had a positive effect on the usefulness, involvement, and participation in water activities; the usefulness of water facilities had a positive and significant impact on the intention to participate in water activities; water leisure involvement had a positive and significant impact on the benefits and the intention to participate in water activities; the intention to participate in water activities had a positive and significant impact on the benefits of water leisure activities. Furthermore, the study found that the intention to participate in water activities had a mediating effect between water leisure involvement and water leisure benefits; water leisure involvement had a mediating effect between the ease of use of water facilities and the intention to participate in water activities; the usefulness of water facilities had a mediating effect between the ease of use of water facilities and the intention to participate in water activities. In addition, the interaction between water leisure involvement and water leisure constraints had an interfering effect on water leisure benefits. Accordingly, recommendations for promotion and implementation are provided. Based on the TAM, the study provided suggestions for implementing water leisure sports to promote college students' participation behavior in water leisure sports.

Deep learning course development and evaluation of artificial intelligence in vocational senior high schools.

This study aimed to develop cross-domain deep learning courses of artificial intelligence in vocational senior high schools and explore its impact on students' learning effects. It initially adopted a literature review to develop a cross-domain SPOC-AIoT Course with SPOC (small private online courses) and the Double Diamond 4D model in vocational senior high schools. Afterward, it adopted participatory action research (PAR) and a questionnaire survey and conducted analyses on the various aspects of the technology acceptance model by SmartPLS. Further, this study explored the impact on the effects of deep learning and knowledge-ability learning of artificial intelligence after 16 weeks of course teaching among 36 Grade I students from the electrical and electronic group of a vocational senior high school. This study revealed that (1) the four stages of the SPOC-AIoT Teaching Mode of the Double Diamond 4D model may effectively guide students to learn AIoT knowledge and skills. (2) Based on the technology acceptance model, the analysis of learning and participation in SmartPLS indicated that this model conformed to the academic fitness requirements of the overall model. (3) After learning with the SPOC-AIoT Teaching Mode, the learning effects of students in AIoT have been significantly improved to a positive aspect. Finally, some suggestions were put forward to promote the development of the SPOC-AIoT Teaching Mode Course in the future.

A tale of tailless.

Drosophila Tailless(Tll) and its vertebrate homologue Tlx are conserved orphan nuclear receptors specifically expressed in the eye and the forebrain. Tll and Tlx act primarily as transcriptional repressors through their interactions with transcriptional corepressors, Atrophin family proteins, and histone-tail/chromatin-modifying factors such as lysine-specific histone demethylase 1 and histone deacetylases. The functional importance of Tll and Tlx is made apparent by the recent discovery that they are expressed in neural stem cells (NSCs) and are required for self-renewal of these cells in both Drosophila and the mouse. This review provides a snapshot of current knowledge about Tll and Tlx and their transcriptional network, which maintains NSCs in developing and adult animals.

Atrophin recruits HDAC1/2 and G9a to modify histone H3K9 and to determine cell fates.

Atrophin family proteins, including the vertebrate arginine-glutamic acid dipeptide repeats protein (RERE) and Drosophila Atrophin (Atro), constitute a new class of nuclear receptor corepressors. Both RERE and Atro share the ELM2 (EGL-27 and MTA1 homology 2) and SANT (SWI3/ADA2/N-CoR/TFIII-B) domains, which are also present in other important transcriptional cofactors. Here, we report that the SANT domain in RERE binds to the histone methyltransferase G9a, and that both the ELM2 and SANT domains orchestrate molecular events that lead to a stable methylation of histone H3-lysine 9. We establish the physiological relevance of these interactions among Atrophin, G9a, and histone deacetylases 1 and 2 in Drosophila by showing that these proteins localize to overlapping chromosomal loci, and act together to suppress wing vein and melanotic-mass formation. This study not only shows a new function of the SANT domain and establishes its connection with the ELM2 domain, but also implies that a similar strategy is used by other ELM2-SANT proteins to repress gene transcription and to exert biological effects.

Mutations in NR2E3 can cause dominant or recessive retinal degenerations in the same family.

NR2E3, a photoreceptor-specific nuclear receptor (PNR), represses cone-specific genes and activates several rod-specific genes. In humans, mutations in NR2E3 have been associated with the recessively-inherited enhanced short-wavelength sensitive S-cone syndrome (ESCS) and, recently, with autosomal dominant (ad) retinitis pigmentosa (RP) (adRP). In the present work, we describe two additional families affected by adRP that carry a heterozygous c.166G>A (p.G56R) mutation in the NR2E3 gene. Functional analysis determined the dominant negative activity of the p.G56R mutant protein as the molecular mechanism of adRP. Interestingly, in one pedigree, the most common causal variant for ESCS (p.R311Q) cosegregated with the adRP-linked p.G56R mutation, and the compound heterozygotes exhibited an ESCS-like phenotype, which in 1 of the 2 cases was strikingly "milder" than the patients carrying the p.G56R mutation alone. Impaired repression of cone-specific genes by the corepressors atrophin-1 (dentatorubral-pallidoluysian atrophy [DRPLA] gene product) and atrophin-2 (arginine-glutamic acid dipeptide repeat [RERE] protein) appeared to be a molecular mechanism mediating the beneficial effect of the p.R311Q mutation. Finally, the functional dominance of the p.R311Q variant to the p.G56R mutation is discussed.

A dynamic technique for the treatment of severe or recurrent blepharoptosis: frontalis-orbicularis oculi muscle flap shortening.

BACKGROUND: Severe or recurrent blepharoptosis remains a great challenge to most plastic surgeons. A variety of techniques have been developed according to the function of the levator palpebrae superioris and frontalis muscles. In this study, the frontalis-orbicularis oculi (FOO) muscle flap is designed as an entity to treat severe or recurrent blepharoptosis with satisfactory results. METHODS: Between January 1997 and July 2007, FOO muscle flap shortening was applied to correct severe or recurrent blepharoptosis in 29 patients (38 eyelids), aged from 3 to 77 years. There were 11 males and 18 females, with bilateral ptosis in 9 patients. The follow-up period ranged from 10 to 52 months. RESULTS: Twenty-four patients (82%) had good results, with the degree of ptosis less than 2 mm. The remaining 5 patients had fair results, and received readjustment in 2 cases. CONCLUSION: In our study, fresh cadaver dissection revealed that the frontalis muscle is connected and interdigitated very closely with the orbicularis oculi muscle. Based on the anatomic study and literature review, we suggest that the FOO muscle flap shortening is a good alternative to treat severe or recurrent blepharoptosis.

A new method using epidural catheters in the reconstruction of lacrimal drainage.

Lacrimal outflow obstruction after severance of the duct is a common problem in facial trauma. Conventional treatments include external dacryocystorhinostomy, endoscopic-assisted dacryocystorhinostomy, conjunctivorhinostomy, and a Jones tube bypass. However, the disadvantages of these methods are that the procedures are complicated and there is a high rate of recurrence. From April 2000 to March 2003, seven patients with epiphora after facial trauma had their lacrimal ducts drained with epidural catheters. The V-M shape incision was used with an epidural catheter placed as a stent for six months. After removal of the tube, all patients recovered fully from the epiphora during the follow-up period, and there were no complications.

Spectrophotometric determination of deacetylation degree of chitinous materials dissolved in phosphoric acid.

A simple spectrophotometric method is proposed for determining deacetylation degrees (DD) of chitinous materials using phosphoric acid as the UV-transparent solvent system. Calibrating by the extinction coefficients (A(210)) of D-glucosamine and N-acetyl-D-glucosamine, DD values (24-88%) were computed numerically. The results correlated well (R(2) = 0.9805, n = 50) with those obtained by solid-state (13)C NMR. Comparison of the results obtained by the proposed UV method and solid-state (13)C NMR.

Case studies in contact burns caused by exhaust pipes of motorcycles.

Contact burns caused by the exhaust pipe of motorcycles are rarely reported. We performed retrospective studies of such cases in 78 patients with complete records. The majority of victims were unmarried (75.7%), young (<25 years, 70.5%), and female (69.3%), dressed mostly in short pants or mini skirts (75.7%). The burn accident occurred mostly in late spring and early summer (52.7%), during rush hours (57.7%), and during parking the motorcycles (65.4%). The burn wounds located mostly on the lateral aspect (46.2%) of the lower leg, usually took 3-4 weeks for complete healing. Continuous monitoring of the exhaust pipe and its outside cover on moving motorcycles showed that the temperature reached 170-250 and 40-60 degrees C, respectively. For the prevention of these injuries, our suggestions include well-designed external shield with adequate separation from the exhaust pipe, motorcycle parking lots of adequate width (>120cm), the wearing of trousers by motorcyclists, decrease of the density of motorcycle traffic, and development of the electric assisted cycle in place of the fuel-driven motorcycle.

The simultaneous combination of implants and tram flaps for an aesthetically pleasing breast.

In Taiwan, there have quite often been incidences when patients have had more abundant abdominal tissue to make a TRAM flap with a volume larger than the contralateral breast. In these situations, we usually recommend performing contralateral augmentation mammoplasty with a saline implant while undergoing TRAM flap reconstruction. From February 1997 to Mar 2001, 250 breast cancer patients underwent immediate pedicled TRAM flap reconstructions at Kaohsiung Medical University Hospital. Of these, 10 cases not only had TRAM flaps, but also simultaneous insertion of a prosthesis into the contralateral/bilateral breast to form a more pleasing breast mound. These were all saline implants. Each patient was young (aged 31-51 years) and had small to medium sized breasts. During the procedure, the implants were placed in a submuscular pocket formed by the pectoralis major muscle. There were no significant complications or failures. All breasts have remained soft and natural-looking during the follow-up period. Nine of 10 patients appreciated this procedure, and 8 of them would agree to convince other patients of the benefits of this operation. Using pedicled TRAM flaps and saline breast implants can achieve immediate breast reconstruction without the need for prolonged tissue expansion or an obvious back scar. Aesthetic results are excellent and the immediate use of an implant does not appear to pose a risk to the success of the pedicle transfer. It is a good alternative for breast cancer patients with previous hypoplasia of the breasts to achieve simultaneous therapeutic and cosmetic results.

The transcriptional corepressor SMRTER influences both Notch and ecdysone signaling during Drosophila development.

SMRTER (SMRT-related and ecdysone receptor interacting factor) is the Drosophila homologue of the vertebrate proteins SMRT and N-CoR, and forms with them a well-conserved family of transcriptional corepressors. Molecular characterization of SMRT-family proteins in cultured cells has implicated them in a wide range of transcriptional regulatory pathways. However, little is currently known about how this conserved class of transcriptional corepressors regulates the development of particular tissues via specific pathways. In this study, through our characterization of multiple Smrter (Smr) mutant lines, mosaic analysis of a loss-of-function Smr allele, and studies of two independent Smr RNAi fly lines, we report that SMRTER is required for the development of both ovarian follicle cells and the wing. In these two tissues, SMRTER inhibits not only the ecdysone pathway, but also the Notch pathway. We differentiate SMRTER's influence on these two signaling pathways by showing that SMRTER inhibits the Notch pathway, but not the ecdysone pathway, in a spatiotemporally restricted manner. We further confirm the likely involvement of SMRTER in the Notch pathway by demonstrating a direct interaction between SMRTER and Suppressor of Hairless [Su(H)], a DNA-binding transcription factor pivotal in the Notch pathway, and the colocalization of both proteins at many chromosomal regions in salivary glands. Based on our results, we propose that SMRTER regulates the Notch pathway through its association with Su(H), and that overcoming a SMRTER-mediated transcriptional repression barrier may represent a key mechanism used by the Notch pathway to control the precise timing of events and the formation of sharp boundaries between cells in multiple tissues during development.

Atrophin proteins: an overview of a new class of nuclear receptor corepressors.

The normal development and physiological functions of multicellular organisms are regulated by complex gene transcriptional networks that include myriad transcription factors, their associating coregulators, and multiple chromatin-modifying factors. Aberrant gene transcriptional regulation resulting from mutations among these elements often leads to developmental defects and diseases. This review article concentrates on the Atrophin family proteins, including vertebrate Atrophin-1 (ATN1), vertebrate arginine-glutamic acid dipeptide repeats protein (RERE), and Drosophila Atrophin (Atro), which we recently identified as nuclear receptor corepressors. Disruption of Atrophin-mediated pathways causes multiple developmental defects in mouse, zebrafish, and Drosophila, while an aberrant form of ATN1 and altered expression levels of RERE are associated with neurodegenerative disease and cancer in humans, respectively. We here provide an overview of current knowledge about these Atrophin proteins. We hope that this information on Atrophin proteins may help stimulate fresh ideas about how this newly identified class of nuclear receptor corepressors aids specific nuclear receptors and other transcriptional factors in regulating gene transcription, manifesting physiological effects, and causing diseases.

The neurodegenerative disease protein ataxin-1 antagonizes the neuronal survival function of myocyte enhancer factor-2.

Ataxin-1 is a neurodegenerative disorder protein whose mutant form causes spinocerebellar ataxia type-1 (SCA1). Evidence suggests that ataxin-1 may function as a transcription repressor. However, neither the importance of this putative transcriptional repression activity in neural cytotoxicity nor the transcriptional targets of ataxin-1 are known. Here we identify the MEF2-HDAC4 transcriptional complex involved in neuron survival as a target of ataxin-1. We show that ataxin-1 binds specifically to histone deacetylase-4 (HDAC4) and MEF2 and colocalizes with them in nuclear inclusion bodies. Significantly, these interactions are greatly reduced by the S776A mutation, which largely abrogates the cytotoxicity of ataxin-1. Supporting the importance of these interactions, we show that wild type ataxin-1 represses MEF2-dependent transcription, whereas the S776A mutant is less potent. Furthermore, overexpression of MEF2 can partially reverse cytotoxicity caused by ataxin-1. Our results identify the MEF2-HDAC4 complex as a target for ataxin-1 transcriptional repression activity and suggest a novel pathogenic mechanism whereby ataxin-1 sequesters and inhibits the neuronal survival factor MEF2.

The use of portable computer for information acquirement during anesthesiologist's ward round in acute pain service.

BACKGROUND: The Acute Pain Service Information Management System (APSIMS), as we coined, is the utilization of a portable computer to register the data of the patients who need acute pain management during anesthesiologist's ward round. Initially, the data of the daily acute pain assessment at the ward are recorded on a sheet of paper by the rounding anesthesiologist, which are subsequently entered into the hospital main frame computer by an anesthetic nurse. In order to save manpower in data entry, we planned to introduce the personal digital assistant (PDA) into acute pain assessment. The anesthesiologist can record a patient's data directly into the PDA device at the bedside. After acute pain assessment is finished, we can directly up load the data from the PDA to the hospital mainframe computer without the need of further manpower for doing data input. This study was to evaluate the use of PDA for acute pain assessment and compare the PDA-based method with that of the current paper-transcription method in work efficiency. METHODS: Two computer applications were developed: the APS Mobile Assistant and the Data Transformation Wizard (DTW). The APS Mobile Assistant is a PDA application running on a portable computer with Windows Mobile 2003 operation system. The anesthesiologist can use this application to perform APS assessment at the bedside. The Data Transformation Wizard is a PC application which can transfer data from the PDA device to the hospital mainframe computer, by which the data in the PDA system can be integrated into the hospital information system. The evaluation included the reckoning of the timings of two periods i.e. the time spent by the physician to perform acute pain assessment at the bedside and the time required for data management by the nurse. To compare the paper-transcription method with the PDA-based technique, the Student's t test was performed to assess the data of time of each category collected. A P value less than 0.05 was considered to be significant. RESULTS: When the time required for assessment of acute pain was determined, no statistically significant difference was observed between the use of the paper-transcription-based system and the PDA system (P = 0.258). In comparison the PDA system was clearly shown to facilitate faster management of data (Paper-transcription method: 1.57 +/- 0.08 min per patient compared with PDA-based method: 0.24 +/- 0.01 min per patient, P < 0.0001). CONCLUSIONS: Implementation of PDA device during APS assessment can provide the anesthesiologists with more time to acquire information during APS visits. Using the PDA technology in clinical settings can increase work efficiency. We can save manpower and are convinced that data collection is more complete with the use of a PDA system.

Histone deacetylase-associating Atrophin proteins are nuclear receptor corepressors.

Drosophila Tailless (Tll) is an orphan nuclear receptor involved in embryonic segmentation and neurogenesis. Although Tll exerts potent transcriptional repressive effects, the underlying molecular mechanisms have not been determined. Using the established regulation of knirps by tll as a paradigm, we report that repression of knirps by Tll involves Atrophin, which is related to vertebrate Atrophin-1 and Atrophin-2. Atrophin interacts with Tll physically and genetically, and both proteins localize to the same knirps promoter region. Because Atrophin proteins interact with additional nuclear receptors and Atrophin-2 selectively binds histone deacetylase 1/2 (HDAC1/2) through its ELM2 (EGL-27 and MTA1 homology 2)/SANT (SWI3/ADA2/N-CoR/TFIII-B) domains, our study establishes that Atrophin proteins represent a novel class of nuclear receptor corepressors.

Boat, an AXH domain protein, suppresses the cytotoxicity of mutant ataxin-1.

Ataxin-1 is a neurodegenerative disorder protein whose glutamine-repeat expanded form causes spinocerebellar ataxia type 1 (SCA1) in humans and exerts cytotoxicity in Drosophila and mouse. We report here that the cytotoxicity caused by ataxin-1 is modulated by association with a related protein, Brother of ataxin-1 (Boat). Boat and ataxin-1 share a conserved AXH (ataxin-1 and HMG-box protein 1) domain, which is essential for both proteins' interactions with the transcriptional corepressor SMRT and its Drosophila homolog, SMRTER. The Boat-ataxin-1 interaction is mediated through multiple regions in both proteins, including a newly identified NBA (N-terminal region of Boat and ataxin-1) domain. We investigated the physiological relevance of the Boat-ataxin-1 interaction in Drosophila and discovered that a mutant ataxin-1-mediated eye defect is suppressed by ataxin-1's association with Boat. Correspondingly, in transgenic SCA1 mouse, Boat expression is greatly reduced in Purkinje cells, the primary targets of SCA1. Our study thus establishes that Boat is an in vivo binding partner of ataxin-1 whose altered expression in Purkinje cells may contribute to their degeneration in SCA1 animals.

Nuclear receptor recruitment of histone-modifying enzymes to target gene promoters.

Nuclear receptors (NRs) compose one of the largest known families of eukaryotic transcription factors and, as such, serve as a paradigm for understanding the fundamental molecular mechanisms of eukaryotic transcriptional regulation. The packaging of eukaryotic genomic DNA into a higher ordered chromatin structure, which generally acts as a barrier to transcription by inhibiting transcription factor accessibility, has a major influence on the mechanisms by which NRs activate or repress gene expression. A major breakthrough in the field's understanding of these mechanisms comes from the recent identification of NR-associated coregulatory factors (i.e., coactivators and corepressors). Although several of these NR cofactors are involved in chromatin remodeling and facilitating the recruitment of the basal transcription machinery, the focus of this chapter is on NR coactivators and corepressors that act to covalently modify the amino-terminal tails of core histones. These modifications (acetylation, methylation, and phosphorylation) are thought to directly affect chromatin structure and?or serve as binding surfaces for other coregulatory proteins. This chapter presents the most current models for NR recruitment of histone-modifying enzymes and then summarizes their functional importance in NR-associated gene expression.

A new technique for levator lengthening to treat upper eyelid retraction: the orbital septal flap.

Correction of upper eyelid retraction can be achieved by numerous techniques. We have developed a new flap, the orbital septal flap, to interpose between the recessed levator complex and the tarsus to correct the retracted upper eyelid of a young girl. The orbital septum is a facial structure; it is readily available and easy to dissect. The flap acts like a vascularited spacer without the problem of resorption; normal anatomical continuity of the levator mechanism can be functionally restored. We believe the orbital septal flap is a promising technique for correcting upper eyelid retraction; however, more case studies are needed.