[Early death and causes of death of patients with autism spectrum disorders: A systematic review]

To study of premature/early death of autistic patients from the perspective of life course can help families, medical institutions and policy makers better deal with the adverse effects of autism. Several studies have shown that autistic patients have a high risk of death, however, the results are still inconsistent. To assess the risk of mortality among the autistic patients, we undertook a comprehensive search of MEDLINE, Web of Science and EMBASE databases. This paper reviewed the studies on the negative disease outcomes of autism spectrum disorders, including the risk of death, causes of death and several research hotspots in this field. Strict inclusion/exclusion criteria were used. Information was extracted from selected papers, tabulated and synthesized. In the study, 15 studies were included, with a total of 216 045 individuals. The main outcome was all-cause mortality in association with autism and the secondary outcome was cause-specific mortality. The results showed that all-cause mortality was higher for the autistic patients (RR=2.32, 95%CI: 1.98-2.72, I²=87.1%, P < 0.001). Risk ratio showed a greater inequality for female than male (male: RR=2.00, 95%CI: 1.57-2.55, I²=93.2%, P < 0.001; female: RR=4.66, 95%CI: 3.30-6.58, I²=92.0%, P < 0.001). Compared with the unnatural death, the risk of natural death was higher (RR=3.44, 95%CI: 1.27-9.26, I²=80.2%, P=0.025). As autism had many comorbidities, which would bring more health risks and natural deaths possibilities. There were some structural differences in unnatural death. Accidental injury death and suicide were two kinds of causes. Lacking social skills would weaken the ability to ask for help when encountering injuries. This paper put forward some suggestions for futures. First, to well study the comorbidity can reduce the risk of death from a medical point of view. Second, the scientists and policymakers should pay attention to the social environment and provide a safer environment for the autistic patients. Third, for women and for adolescents without cognitive impairment, due to their high risk of suicide, the society should provide them with more supportive social networks and improve their life satisfaction. Fourth, it is necessary to balance the rehabilitation resources in various regions in China and provide more high-quality lifelong rehabilitation monitoring and care services.

[Changes of brain network characteristics in patients with depression before and after precise repetitive transcranial magnetic stimulation]

Objective: To investigate the changes of brain network characteristics in patients with depression before and after precise repetitive transcranial magnetic stimulation (rTMS) treatment. Methods: Patients with depression in the Second Affiliated Hospital of Xinxiang Medical University and healthy volunteers in the community of Xinxiang city from February 2018 to March 2019 were simultaneously recruited. The left dorsolateral prefrontal cortex was precisely selected as the stimulation target through the latest Human Brainnetome Atlas, and the near infrared navigation was used to achieve accurate brain stimulation treatment in combination with the structural magnetic resonance data. Moreover, functional connectivity was analyzed before and after rTMS treatment in significantly altered brain areas of patients with depression. Results: Nineteen patients (11 males and 8 females) with depression were included, aged (34±11) years. Meanwhile, 22 healthy controls (9 males and 13 females), aged (30±9) years, were also enrolled. Functional connectivity of insular cortex was decreased in depression patients when the insula was analyzed as the target area (P<0.05). The functional connection from insula to middle frontal lobe and superior parietal lobe in patients with depression decreased before rTMS treatment (P<0.05), but increased after rTMS treatment (P<0.05). The functional connection between dIg_L of the insula and the right middle prefrontal lobe was correlated with Beck Anxiety Index (BAI) before rTMS treatment and Beck Depression Index (BDI) after rTMS treatment (r=0.737, P=0.003; r=0.696, P=0.005). Conclusions: Abnormal functional connectivity of insula may be the brain imaging mechanism of rTMS treatment. Precise brain region selection based on Human Brainnetome Atlas provides a new technical method for clinical rTMS precision treatment.

Working Memory of Patients with Mild Cognitive Impairment due to Brain Trauma Based on fNIRS

ABSTRACT

Objective To discuss the activation characteristics of the prefrontal cortex of people with mild cognitive impairment （MCI） due to brain trauma during working memory tasks. Methods The psychological experiment design software E-prime was used and N-back paradigm was adopted as working memory task. Functional near-infrared spectroscopy （fNIRS） was used to detect changes in cortical oxygenated hemoglobin concentrations of 22 channels within the prefrontal lobe of 24 people with MCI due to brain trauma （study group） and 27 healthy volunteers （control group） with matching gender and age. Behavioral data, such as the number of keystroke errors and reaction time, were recorded simultaneously. Independent samples t test and non-parametric test were used to compare the mean value of oxygenated hemoglobin concentration change, the number of key errors and the mean value of reaction time of the two groups in each task. Results （1） The differences in the number of errors and reaction time between the two groups in 1-back and 2-back tasks had statistical significance （P<0.05）.The main effects of task load and group were both significant （task F=14.11, P=0.001 1; group F=10.39, P=0.001 5）. （2） During the 1-back task, the differences in oxygenated hemoglobin concentration changes of the 22 channels between the two groups had no statistical significance （P>0.05）. During the 2-back task, the differences in oxygenated hemoglobin concentration changes of the two groups in channel 2, 3, 7, 9, 10, 11, 14, 15, 18, 19, 21 and 22 had statistical significance （P<0.05）. （3） In the 1-back task, the left frontal pole and dorsolateral prefrontal area in both groups were activated. In the 2-back task, the activation areas of the control group were the left frontal pole area and the left dorsolateral prefrontal area, while that of the study group almost covered most of the left and right frontal pole areas, which were scattered and the right area was activated, too. Conclusion Patients with MCI due to brain trauma have obvious working memory impairment, and during the 2-back working memory task, the activation of the prefrontal lobe decreased, but the activation range was wider.

Application of Mismatch Negative in Evaluation of Severity of Mental Disorders due to Traumatic Brain Injury

Objective To explore the applied value of mismatch negative （MMN） in evaluation of severity of mental disorders due to traumatic brain injury. Methods Thirty-five patients（case group） that conform to the diagnostic criteria of organic （traumatic brain injury） mental disorder in ICD-10 Classification of Mental and Behavioural Disorders criteria were selected. Twenty-four healthy subjects （normal control group） that matched the case group in terms of gender, age composition ratio and educational level were selected. All subjects were evaluated by Activity of Daily Living Scale （ADL） and Social Disability Screening Schedule （SDSS） and then examined by Event-Related Potential （ERP）. A statistical analysis of the data was made by SPSS 22.0 software. Results The 32 patients and 24 normal control subjects completed the study. The scores of ADL and SDSS were significantly higher in the case group than in the normal control group （P<0.05）. The latency of Fz, FCz, Cz and Pz in the case group was significantly longer than that in the normal control group （P<0.05）. In the case group, the latency of Fz, FCz, Cz and Pz was positively correlated with the scores of ADL and SDSS （P<0.05）. The equation can be well fitted with the scores of ADL and SDSS. The latency and amplitude of Fz, FCz, Cz and Pz were used as concomitant variables and whether or not the subjects had mental disorders due to traumatic brain injury as dependent variables. Conclusion The latency of MMN can be used as an indicator in potential evaluation of the severity of mental disorders due to traumatic brain injury, which means that the longer the latency of MMN is, the more severe mental disorders due to traumatic brain injury may be. The combined application of ADL, SDSS and MMN can be an objective indicator in preliminary judgment of mental disorders due to traumatic brain injury.

Glucohexaose-induced protein phosphatase 2C regulates cell redox status of cucumber seedling

Protein Phosphatase 2C (PP2C) is an important phosphatase-like protein in eukaryotic organisms that can negatively regulate protein kinase cascade abscisic acid (ABA) signal system through phosphorylation and carry out vital roles in various cell processes. The previous study indicated that the accumulation of reactive oxygen species (ROS) is a part of mechanism of glucohexaose-induced resistance in cucumber cotyledons, and CsPP2C80s might play a crucial role in processes related to ROS produce and signal transduction. To identify the mechanism of CsPP2C80s involved in glucohexaose and ABA signaling regulating cell redox status, the effects of glucohexaose and ROS inhibitor pretreatment on endogenous ABA content and ABA signaling genes expression levels of cucumber seedlings were analysed. These results suggest that cucumber CsPP2C80s are involved in ROS accumulation and ABA signal transduction pathway induced by glucohexaose, CsPP2C80s play a positive regulatory role in process of ABA combined with ABA receptors (PYLs) to activate SNF1-related protein kinases 2 (SnRK2s) and regulate NADPH oxidase to produce extracellular hydrogen peroxide (H2O2), providing unequivocal molecular evidence of PP2C-mediated ABA response mechanisms functioning in cell redox status induced by glucohexaose.

[Applied Value of Electroencephalogram in Assessment of Mild Psychiatry Impairment]

OBJECTIVES

To explore the applied value of electroencephalogram （EEG） in assessment of psychiatric impairment among patients with mental disorders due to traumatic brain injury.

METHODS

According to the ICD-10, a total of 271 subjects were enrolled and assessed with the criterion of mental disorders due to traumatic brain injury. Activity of Daily Living Scale （ADL）, Functional Activities Questionnaire （FAQ） and Social Disability Screening Schedule （SDSS） were used to evaluate the severity of patients. All the participants were tested by Wechsler Adult Intelligence Scale （WAIS） and examined by EEG.

RESULTS

Totally 215 patients accomplished the study. The results of Glasgow Coma Scale （GCS）, the severity of craniocerebral injury and the scores of FAQ, SDSS and ADL showed significant difference among the patients with different severity of EEG （P<0.05）. The grades of psychiatric impairment showed significant difference among the patients with different abnormal EEG （P<0.05）.

CONCLUSIONS

EEG can reflect the severity of craniocerebral injury, assist evaluate the social function and activity of daily living of patients with mental disorders due to traumatic brain injury, and distinguish the mild psychiatric impairment grades, which suggest that EEG has a certain reference value in the assessment of psychiatric impairment.

[Changes and the impact on immune function of opioid-dependent subjects by Jitai tabelets during the withdrawal stage]

Objective: To detect the changes in the immune function of opioid-dependent subjects during the withdrawal stage through the administration of Jitai tablet. Methods: Subjects were treated as Jitai tablet alone, Jitai tablet plus buprenorphine and placebo, in a randomized,double-blind, placebo-controlled trial. Before and after the 14(th) day of withdrawal, levels of immunoglobulin (IgM, IgA, IgG), T cell subsets (CD(3)(+), CD(4)(+), CD(8)(+), CD(4)(+)/CD(8)(+)) and cytokines (IL-2, IFN-γ, IL-4, IFN-γ/IL-4) were detected. Results: Compared with healthy people, immunity function before withdrawal among the opioid abusers showed higher levels of IgM, IL-2, IFN-γ, IL-4 and lower level of CD(3)(+)T, as (1.67±0.87) g/L, (14.44±13.50)%, (20.23±15.10)%, (1.97±1.59)%, (47.01±13.62)%, respectively, with difference statistically significant (P<0.05). There was no big difference of other immunity indicators between the two groups (P>0.05). At the 14(th) day of withdrawal in placebo group, levels of IL-4 returned to normal while IFN-γ/IL-4 ratio increased by 3.43 times (P<0.05). Levels of IgA, IgG, CD(4)(+) and CD(4)(+)/CD(8)(+) ratio fluctuated within normal range. There were no significant changes in other immunity indicators (P>0.05). Compared with placebo group, fluctuation of IgG and IgM decreased in Jitai group during withdrawal period, together with a normal level of IgM at the 14(th) day. Level of IL-4 abnormally rose up by 0.54 times in Jitai tablet plus buprenorphine group, while IFN-γ/IL-4 ratio been switched back at the 14(th) day of withdrawal. Other immune indicators were not affected by medical interventions. Conclusion: We noticed that certain impairment of the immune function might be restored by Jitai tablet during the withdrawal period.

Complete mitochondrial genome sequence and gene organization of Chinese indigenous chickens with phylogenetic considerations

In this study, we sequenced the complete mitochondrial DNA of Chinese indigenous Jinhu Black-bone and Rugao chickens. The two chicken mitochondrial genomes were deposited in GenBank under accession Nos. KP742951 and KR347464, respectively. The complete mitochondrial genomes of Jinhu Black-bone and Rugao chickens were sequenced and found to span 16,785 and 16,786 bp, respectively, and consisted of 22 tRNA genes, two rRNA genes (12S rRNA and 16S rRNA), 13 protein-coding genes, and one control region (D-loop). The majority of genes were positioned on the H-strand, and the ND6 and eight tRNA genes were found to be encoded on the L-strand. The mitogenomes showed a similar gene order to that of the published Gallus gallus genome, as neither included a control region. The overall base composition of the genome of the two chickens was A = 30.22/30.28%, G = 13.57/13.49%, T = 23.74/23.76%, and C = 32.48/32.48%. Nucleotide skewness of the coding strands of the two chicken genomes (AT-skew = 0.12, GC-skew = -0.41) was biased towards T and G. Phylogenetic analysis revealed 29 subspecies, and the molecular genetic relationship among the 29 subspecies was identical to that of traditional taxonomy.

Single nucleotide polymorphisms in the mitochondrial displacement loop and age-at-onset of non-small cell lung cancer

The associations between single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) and cancer risk and disease outcome have been extensively analyzed. We investigated the association between age-at-onset and SNPs in the mitochondrial D-loop using a population-based series of non-small cell lung cancer (NSCLC) patients. The D-loop region of mtDNA from NSCLC patients was amplified and sequenced. The age-at-onset curve of NSCLC patients was calculated using the Kaplan-Meier method at each SNP site and values were compared using the log-rank test. The SNP sites of nucleotides 200G/A and 16362T/C were identified to determine their association with age-at-onset of NSCLC using the log-rank test. The nucleotide 207G/A was identified for its association with age-at-onset at a borderline significance level (P = 0.060). We found that genetic polymorphisms in the D-loop were predictive markers for age-at-onset in NSCLC patients. Accordingly, the analysis of genetic polymorphisms in the mitochondrial D-loop can be used to identify NSCLC patient subgroups at high risk of early onset.

Trichosanthes kirilowii: A New Host of Cucurbit mild mosaic virus in China

Chinese cucumber (Trichosanthes kirilowii Maxim.) is a type of perennial liana plant of the Cucurbitaceae family that is mainly distributed in East Asia and northern Australia. It is an important medicinal plant and commonly used in Chinese herbalism, where it is considered to be one of the 50 fundamental herbs (2). During the summer and autumn of 2012, T. kirilowii plants showing symptoms of mild mosaic on the upper leaves and bright yellow color on the lower leaves were observed in the Haidian district of Beijing, China. Recently similar symptoms induced by Cucurbit mild mosaic virus (CuMMV) on squash have been reported. CuMMV is a new member of the genus Fabavirus in the Comovirinae subfamily, discovered in China in 2006 (1). Total RNA was extracted from five leaf samples of independent plants and used for reverse transcription with an oligo (dT)₁₈ primer, followed by PCR with a pair of CuMMV virus-specific primers FaR₁3012F (5'-CGAGTGCGAGTTAGAAATTGGGATG-3') and FaR₁5783R (5'-TCACTTTGAGGTGATAAAACAATCC-3') to amplify a 2,772-bp fragment including RNA-dependent RNA polymerase (RdRp) coding region. The expected target fragment was obtained in all symptomatic plant samples but not from an asymptomatic plant. Nucleotide sequence comparison analysis showed that the virus isolated from T. kirilowii (GenBank Accession No. KC959843) had 95.33% nucleotide identity and 99.15% amino acid identity in the RdRp sequence with a CuMMV isolate from squash (GenBank Accession No. FJ194941) (1). In addition, symptomatic samples tested positive for CuMMV by Western blot using CuMMV small coat protein (SCP) specific polyclonal antibody (1). To our knowledge, this is the first report of T. kirilowii as natural host of CuMMV in China. The impact of CuMMV on T. kirilowii production remains to be determined; however, the extended host range for this virus suggests a potential threat of CuMMV to cucurbit crops in China. References: (1) S. W. Dong et al. Arch. Virol.157:597, 2012. (2) J. H. Hong et al. China Pharmacist 7:561, 2004.

Cell wall degradation and the dynamic changes of Ca2+ and related enzymes in the developing aerenchyma of wheat (Triticum aestivum L.) under waterlogging

This research was aimed to study the cell wall degradation and the dynamic changes of Ca2+ and related enzymes in developing aerenchyma of wheat root under waterlogging. An examination of morphological development by light and electron microscope revealed that the structure of cell wall in middle cortical cells remained intact after 12 h of waterlogging and turned thinner after waterlogging for 24 h. At 48 h, the aerenchyma has been formed. The cellulase activity gradually increased in middle cortical cells within 24 h of waterlogging, and decreased with the formation of aerenchyma. Fluorescence detection and subcellular localization of Ca2+ showed the dynamic changing of Ca2+ at the cellular and subcellular levels during the development of aerenchyma. The activity of Ca2+-ATPase enhanced markedly in intercellular space, plasma membrane and tonoplast of some middle cortical cells after 8 h of waterlogging and remained high after 24 h, but it decreased after 48 h of waterlogging. All these suggests that cellulase, Ca2+ and Ca2+-ATPase show a dynamic distribution during the aerenchyma development which associated with the cell wall degradation of middle cortical cells. Moreover, there is a feedback regulation between Ca2+ and Ca2+-ATPase.

First Report of Leaf Spot Disease Caused by Exserohilum rostratum on Pineapple in Hainan Province, China

Pineapple (Ananas comosus (L.) Merr.) is an important perennial monocotyledonous plant that serves as an important fruit crop globally and is also produced in the Hainan Province of China where production in 2009 was 296,600 t. In July 2009, atypical symptoms of a leaf spot disease were observed on mature pineapple leaves in Chengmai County; approximately 15% of plants propagated from suckers became symptomatic after 150 to 300 days, eventually causing a 3 to 10% yield loss. In the initial infection stage, grayish white-to-yellowish white spots emerged on the leaf surfaces that ranged from 1.0 to 2.4 × 0.3 to 0.7 cm; black specks were not always present in the spots. Leaf spots also had distinctive light brown-to-reddish brown banding pattern on the edges. Several spots would often merge to form large lesions, 6.5 to 15.4 × 2.5 to 5.6 cm, covering more than 67% of the leaf surface, which can lead to death of the plant. Infected pineapple leaves collected from an orchard of Chengmai County were surface sterilized (75% ethanol for 30 s, 0.1% HgCl₂ for 2 min, and rinsed three times in sterile distilled water). Leaf pieces were placed on potato dextrose agar medium and then incubated at 25°C. The emerging fungal colonies were grayish white to brown. Similar strains were obtained from Qionghai City and Wanning City subsequently. Two isolates, ITF0706-1 and ITF0706-2, were used in confirmation of the identity of the pathogen and in pathogenicity tests. Colonies were fast growing (more than 15 mm per day at 25 to 30°C) with dense aerial mycelia. Conidia were fusiform, pyriform to oval or cylindrical, olive brown to dark brown, 3 to 10 septate (typically 5 to 8), 33.2 to 102.5 × 9.0 to 21.3 μm, with a strongly protruding hilum bulged from the basal cell, which were similar to the Type A conidia described by Lin et al. (3). The strains were subjected to PCR amplification of the internal transcribed spacer (ITS)1-5.8S-ITS2 regions with universal primer pair ITS1/ITS4. The ITS sequence comparisons (GenBank Accession Nos. JN711431 and JN711432) shared between 99.60 and 99.83% identity with the isolate CATAS-ER01 (GenBank Accession No. GQ169762). According to morphological and molecular analysis, the two strains were identified as Exserohilum rostratum (Drechs.) Leonard & Suggs. Pathogenicity experiments were conducted five times and carried out by spraying a conidial suspension (10⁵ CFU/ml) on newly matured leaves of healthy pineapple plants; plants sprayed with sterile water served as the negative control. Plants were incubated in the growth chamber at 20 to 25°C. Symptoms of leaf spot developed on test plants 7 days after inoculation while the control plants remained asymptomatic. Koch's postulates were fulfilled with the reisolation of the two fungal strains. Currently, E. rostratum is one of the most common pathogens on Bromeliads in Florida (2) and has been reported on Zea mays (4), Musa paradisiacal (3), and Calathea picturata (1) in China, but to our knowledge, this is the first report of leaf spot disease caused by E. rostratum on pineapple in Hainan Province of P.R. China. References: (1) L. L. Chern et al. Plant Dis. 95:1033, 2011. (2) R. M. Leahy. Plant Pathol. Circ. No. 393. Florida Department of Agriculture and Consumer Services Division of Plant Industry, 1999. (3) S. H. Lin et al. Australas. Plant Pathol. 40:246, 2011. (4) J. N. Tsai et al. Plant Pathol. Bull. 10:181, 2001.

Polo-like kinase-1 in porcine oocyte meiotic maturation, fertilization and early embryonic mitosis

Polo-like kinases (Plks) are a family of serine/threonine protein kinases that regulate multiple stages of mitosis. Expression and distribution of polo-like kinase 1 (Plk1) were characterized during porcine oocyte maturation, fertilization and early embryo development in vitro, as well as after microtubule polymerization modulation. The quantity of Plk1 protein remained stable during meiotic maturation. Plk1 accumulated in the germinal vesicles (GV) in GV stage oocytes. After germinal vesicle breakdown (GVBD), Plk1 was localized to the spindle poles at metaphase I (MI) stage, and then translocated to the middle region of the spindle at anaphase-telophase I. Plk1 was also localized in MII spindle poles and on the spindle fibers and on the middle region of anaphase-telophase II spindles. Plk1 was not found in the spindle region when colchicine was used to inhibit microtubule organization, while it accumulated as several dots in the cytoplasm after taxol treatment. After fertilization, Plk1 concentrated around the female and male pronuclei. During early embryo development, Plk1 was found to be in association with the mitotic spindle at metaphase, but distributed diffusely in the cytoplasm at interphase. Our results suggest that Plk1 is a pivotal regulator of microtubule organization and cytokinesis during porcine oocyte meiotic maturation, fertilization, and early embryo cleavage in pig oocytes.

Analysis of pollutant levels in central Hong Kong applying neural network method with particle swarm optimization

Air pollution has emerged as an imminent issue in modern society. Prediction of pollutant levels is an important research topic in atmospheric environment today. For fulfilling such prediction, the use of neural network (NN), and in particular the multi-layer perceptrons, has presented to be a cost-effective technique superior to traditional statistical methods. But their training, usually with back-propagation (BP) algorithm or other gradient algorithms, is often with certain drawbacks, such as: 1) very slow convergence, and 2) easily getting stuck in a local minimum. In this paper, a newly developed method, particle swarm optimization (PSO) model, is adopted to train perceptrons, to predict pollutant levels, and as a result, a PSO-based neural network approach is presented. The approach is demonstrated to be feasible and effective by predicting some real air-quality problems.

[Protein kinases involved in the meiotic maturation and fertilization of oocyte]

The meiosis and fertilization of vertebrate oocyte are extensively regulated by various protein kinases. Recently, a great progress has been achieved in the studies on the molecular mechanisms of oocyte maturation, activation and fertilization. MPF and MAPK were found to be the key modulators of the cell cycle in oocyte, whose activation and inactivation result in the entry, arrest and exit of meiosis. Many protein kinases influence the meiosis by stimulating or inhibiting the activity of MPF and MAPK. Polo-like kinase activates MPF, whereas Mos initiates oocyte maturation and sustains MII arrest by activating MAPK. CaMK II down-regulates the MPF level through an ubiquitin-dependent pathway, which leads to the breakthrough of M phase arrest. Furthermore, p90(rsk) is involved in themeiosis regulation as a downstream regulator of MAPK; protein kinase C induces cortical granule exocytosis after fertilization and inhibits MAPK activity during maturation; and tyrosine protein kinase family members modulate the calcium release induced by fertilization. The cooperation of these protein kinases is essential to the development and fertilization of the oocyte.

High-copy-number expression of Sub2p, a member of the RNA helicase superfamily, suppresses hpr1-mediated genomic instability

We report on a novel role for a pre-mRNA splicing component in genome stability. The Hpr1 protein, a component of an RNA polymerase II complex and required for transcription elongation, is also required for genome stability. Deletion of HPR1 results in a 1,000-fold increase in genome instability, detected as direct-repeat instability. This instability can be suppressed by the high-copy-number SUB2 gene, which is the Saccharomyces cerevisiae homologue of the human splicing factor hUAP56. Although SUB2 is essential, conditional alleles grown at the permissive temperature complement the essential function of SUB2 yet reveal nonessential phenotypes. These studies have uncovered a role for SUB2 in preventing genome instability. The genomic instability observed in sub2 mutants can be suppressed by high-copy-number HPR1. A deletion mutant of CDC73, a component of a PolII complex, is also unstable for direct repeats. This too is suppressed by high-copy-number SUB2. Thus, defects in both the transcriptional machinery and the pre-mRNA splicing machinery can be sources of genome instability. The ability of a pre-mRNA splicing factor to suppress the hyperrecombination phenotype of a defective PolII complex raises the possibility of integrating transcription, RNA processing, and genome stability or a second role for SUB2.

Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58-752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon-intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3' UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

Activation of p53 or loss of the Cockayne syndrome group B repair protein causes metaphase fragility of human U1, U2, and 5S genes

Infection by adenovirus 12, transfection with the Ad12 E1B 55 kDa gene, or activation of p53 cause metaphase fragility of four loci (RNU1, PSU1, RNU2, and RN5S) each containing tandemly repeated genes for an abundant small RNA (U1, U2, and 5S RNA). We now show that loss of the Cockayne syndrome group B protein (CSB) or overexpression of the p53 carboxy-terminal domain induces fragility of the same loci; moreover, p53 interacts with CSB in vivo and in vitro. We propose that CSB functions as an elongation factor for transcription of structured RNAs, including some mRNAs. Activation of p53 would inhibit CSB, stalling transcription complexes and locally blocking chromatin condensation. Impaired transcription elongation may also explain the diverse clinical features of Cockayne syndrome.

Expression and characterization of an epididymis-specific gene

A truncated cDNA coding a rabbit epididymal protein (BE-20) was identified in a previous study. In the present study the full-length cDNA was isolated by the method of rapid amplification of cDNA ends. The BE-20 cDNA consisted of 585 bp with a poly(A) tail of 26 residues and an open reading frame composed of 369 bp encoding a deduced polypeptide containing 123 amino acid residues with a calculated molecular mass of 13 kDa. The N-terminus-contained a leucine-rich segment. BE-20 cDNA has about 76.8% homology with the HE4 gene of human epididymis. Northern blot analysis of mRNAs prepared from 17 different human tissues was performed using as probe a 0.5-kb DNA fragment corresponding to a segment of BE-20 cDNA. Positive reaction was elicited only with epididymal mRNA. A DNA fragment corresponding to a section of the open reading frame of BE-20 cDNA was cloned in Escherichia coli under the control of the T7 promoter. The cellular content of the expressed recombinant protein comprised about 55% of the total protein. The chromatographically purified bacterial product migrated as a single band with an estimated M(r) of 15 kDa on analysis by SDS-PAGE. In conclusion, BE-20 cDNA is expressed only in the epididymis. It is structurally related to the four-disulfide core family of extracellular proteinase inhibitors and may be involved in sperm maturation.

A complex containing RNA polymerase II, Paf1p, Cdc73p, Hpr1p, and Ccr4p plays a role in protein kinase C signaling

Yeast contains at least two complex forms of RNA polymerase II (Pol II), one including the Srbps and a second biochemically distinct form defined by the presence of Paf1p and Cdc73p (X. Shi et al., Mol. Cell. Biol. 17:1160-1169, 1997). In this work we demonstrate that Ccr4p and Hpr1p are components of the Paf1p-Cdc73p-Pol II complex. We have found many synthetic genetic interactions between factors within the Paf1p-Cdc73p complex, including the lethality of paf1Delta ccr4Delta, paf1Delta hpr1Delta, ccr4Delta hpr1Delta, and ccr4Delta gal11Delta double mutants. In addition, paf1Delta and ccr4Delta are lethal in combination with srb5Delta, indicating that the factors within and between the two RNA polymerase II complexes have overlapping essential functions. We have used differential display to identify several genes whose expression is affected by mutations in components of the Paf1p-Cdc73p-Pol II complex. Additionally, as previously observed for hpr1Delta, deleting PAF1 or CDC73 leads to elevated recombination between direct repeats. The paf1Delta and ccr4Delta mutations, as well as gal11Delta, demonstrate sensitivity to cell wall-damaging agents, rescue of the temperature-sensitive phenotype by sorbitol, and reduced expression of genes involved in cell wall biosynthesis. This unusual combination of effects on recombination and cell wall integrity has also been observed for mutations in genes in the Pkc1p-Mpk1p kinase cascade. Consistent with a role for this novel form of RNA polymerase II in the Pkc1p-Mpk1p signaling pathway, we find that paf1Delta mpk1Delta and paf1Delta pkc1Delta double mutants do not demonstrate an enhanced phenotype relative to the single mutants. Our observation that the Mpk1p kinase is fully active in a paf1Delta strain indicates that the Paf1p-Cdc73p complex may function downstream of the Pkc1p-Mpk1p cascade to regulate the expression of a subset of yeast genes.

Specific interactions between the K domains of AG and AGLs, members of the MADS domain family of DNA binding proteins

MADS domain (for MCM1, AG, DEFA and SRF) proteins are regulatory proteins found in all major eukaryotic kingdoms. Plant MADS domain regulatory proteins have a region of moderate sequence similarity that has been designated as the K domain, and its predicted coiled-coil structure suggests a role in establishing a protein-protein interaction. In vivo studies with the Arabidopsis AGAMOUS (AG) protein have indicated that the K domain is important for AG function. Using a bait fusion protein containing the K domain and the C-terminal region of AG in a yeast two-hybrid selection, 156 clones that encode potential AG-interacting proteins were identified. These clones each encode one of four highly related MADS domain proteins: AGL2, AGL4, AGL6 and AGL9. Additional analysis showed that the K domain of AG alone was able to bind the K domains of these AGLs. This binding was further confirmed by immunoprecipitation experiments using in vitro synthesized AG and AGL K domains. These results strongly suggest that AG interacts with AGL2, AGL4, AGL6 and AGL9 in vivo. Based on these results and previous observations, it is proposed that the AG function requires interaction with at least one of these AGL proteins, and such interactions contribute to the functional specificity of the AG protein.

Identification of a rabbit epididymal protein gene

A protein designated as BE-20 was purified from cauda epididymal fluid of the rabbit by preparative polyacrylamide gel electrophoresis and HPLC on a mono Q HR5/5 anion exchange column. The purified protein migrated with an estimated Mt of 20,000 when analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The amino acid sequence of the N-terminus of the BE-20 protein was determined. The initial eight amino acid residues were His-Gly-Ala-Asp-Lys-Pro-Gly-Val. The corresponding 23 mer oligonucleotide (5'-CATGGCGCTGACAAGCCTGGGGT-3') was synthesized and used as sense primer with rabbit epididymal mRNA as template in the RT-PCR system. The purified BE-20 cDNA consisted of 499 bp with an open reading frame of 285 bp encoding a deduced polypeptide composed of 95 amino acids. The BE-20 cDNA had 78.5% identity in 479 bp overlap with human epididymis-specific HE4 cDNA. The amino acid sequences of the initial 30 amino acid residues of the N-terminus of the purified protein and the deduced polypeptides were as follows: N-His-Gly-Ala-Asp-Lys-Pro-Gly-Val-Cys-Pro-Gln-Leu-Ser-Ala-Asp-Leu-Asn-Cy s- Thr-Gln-Asp-Cys-Arg-Ala-Asp-Gln-Asp-Cys-Ala-Glu. The deduced polypeptide contained 16 cysteine residues and had partial sequence homology with proteins belonging to the four-disulfide core family of extracellular proteinase inhibitors. The BE-20 protein may play a role in sperm maturation and/or capacitation.

Mutations in the RNA polymerase II transcription machinery suppress the hyperrecombination mutant hpr1 delta of Saccharomyces cerevisiae

The soh1, soh2 and soh4 mutants were isolated as suppressors of the temperature-dependent growth of the hyperrecombination mutant hpr1 of Saccharomyces cerevisiae. Cloning and sequence analysis of these suppressor genes has unexpectedly shown them to code for components of the RNA polymerase II transcription complex. SOH2 is identical to RPB2, which encodes the second largest subunit of RNA polymerase II, and SOH4 is the same as SUA7, encoding the yeast transcription initiation factor TFIIB. SOH1 encodes a novel 14-kD protein with limited sequence similarity to RNA polymerases. Interestingly, SOH1 not only interacts with factors involved in DNA repair, but transcription as well. Thus, the Soh1 protein may serve to couple these two processes. The Soh1 protein interacts with a DNA repair protein, Rad5p, in a two-hybrid system assay. Soh1p may functionally interact with components of the RNA polymerase II complex as suggested from the synthetic lethality observed in soh1 rpb delta 104, soh1 soh2-1 (rpb2), and soh1 soh4 (sua7) double mutants. Because mutations in SOH1, RPB2 and SUA7 suppress the hyperrecombination phenotype of hpr1 mutants, this suggests a link between recombination in direct repeats and transcription.

Characterization of mutations that suppress the temperature-sensitive growth of the hpr1 delta mutant of Saccharomyces cerevisiae

The hpr1 delta 3 mutant of Saccharomyces cerevisiae is temperature-sensitive for growth at 37 degrees and has a 1000-fold increase in deletion of tandem direct repeats. The hyperrecombination phenotype, measured by deletion of a leu2 direct repeat, is partially dependent on the RAD1 and RAD52 gene products, but mutations in these RAD genes do not suppress the temperature-sensitive growth phenotype. Extragenic suppressors of the temperature-sensitive growth have been isolated and characterized. The 14 soh (suppressor of hpr1) mutants recovered represent eight complementation groups, with both dominant and recessive soh alleles. Some of the soh mutants suppress hpr1 hyperrecombination and are distinct from the rad mutants that suppress hpr1 hyperrecombination. Comparisons between the SOH genes and the RAD genes are presented as well as the requirement of RAD genes for the Soh phenotypes. Double soh mutants have been analyzed and reveal three classes of interactions: epistatic suppression of hpr1 hyperrecombination, synergistic suppression of hpr1 hyperrecombination and synthetic lethality. The SOH1 gene has been cloned and sequenced. The null allele is 10-fold increased for recombination as measured by deletion of a leu2 direct repeat.