Characterization of Androgen Receptor Structure and Nucleocytoplasmic Shuttling of the Rice Field Eel

Androgen receptor (AR) plays a critical role in prostate cancer and male sexual differentiation. We have identified AR from a primitive vertebrate with a sex reversal characteristic, the rice field eel. AR of this species (eAR) is distinct from human AR, especially in the ligand binding domain (LBD), and its expression in gonads shows an increasing tendency during gonadal transformation from ovary via ovotestis to testis. eAR has a restricted androgen-dependent transactivation function after a nuclear translocation upon dihydrotestosterone exposure. A functional nuclear localization signal was further identified in the DNA binding domain and hinge region. Although nuclear export is CRM1-independent, eAR has a novel nuclear export signal, which is negatively charged, indicating that a nuclear export pathway may be mediated by electrostatic interaction. Further, our studies have identified critical sequences for ligand binding in the C terminus. A structure of three α-helices in the LBD has been conserved from eels to humans during vertebrate evolution, despite a distinct amino acid sequence. Mutation analysis confirmed that the LBD is essential for dihydrotestosterone-induced nuclear import of eAR and following transactivation function in the nucleus. In addition, eAR interacts with both Sox9a1 and Sox9a2, and their interaction regulates transactivation of eAR. Our data suggest that the primitive species conserves and especially acquires key novel domains, the nuclear export signal and LBD, for the eAR function in spite of a rapid sequence evolution.     

水分胁迫对不同小麦品种光系统功能基因psbA、psbD及cab表达的影响

两种小麦品种绵农4号T r itic u m a e s ti v u m L.c v.M i a n n o n g N o.4和绵农5号T r itic u m a e s ti v u m L.c v.M i a n n o n g N o.5在渐进水分胁迫下相对含水量、质膜相对透性及光系统D C I P2,62二氯酚靛酚光化学还原活性变化的差异显示,绵农5号小麦比绵农4号小麦具有较高的水分胁迫耐受力.进而对比了水分胁迫对这两种耐旱性不同的小麦品种的光系统在基因转录及蛋白代谢等方面的影响.结果表明:渐进水分胁迫下,两种小麦的光系统主要基因p sb A、p sb D、c a b的转录本水平及其编码蛋白D1,D2、L H C的稳态含量分别下降20%及14%以上,而绵农5号c a b基因的转录水平下降程度39.5%与绵农4号61.8%相比明显缓慢,这可能是其具有较高耐旱性的一个重要原因.     

Single nucleotide polymorphisms,haplotypes and combined genotypes of lactoferrin gene and their associations with mastitis in Chinese Holstein cattle

Lactoferrin (Lf) is naturally produced by the mammary gland, having biological functions of antibacterial and anti-inflammatory activities. To investigate whether the Lf gene is associated with mastitis in dairy cattle, a DNA sequencing approach was used to identify single nucleotide polymorphisms (SNPs) in the gene. Three previously reported SNPs in the 5′ flanking region and one novel SNP in exon1 of Lf gene were identified. A total of 353 individuals from Holstein cattle populations were genotyped for their SNPs using Created Restriction Site PCR (CRS-PCR) and PCR-RFLP methods. Twenty-two and nineteen combinations of three SNPs (g.3440T>G, g.3879_3880insG, and g.4432T>C) and another three SNPs (g.3429G>A, g.3440T>G, g.3879_3880insG) were observed, respectively. The result of haplotype analysis of four SNPs showed that fourteen different haplotypes were identified. Two major haplotypes (GECB and GECA) occurred with a frequency of 22.5 and 18.5% in the study population, respectively. Statistical analyses revealed no significant association between one single SNP of Lf gene and SCS, whereas significant associations between their combined genotypes of three SNPs, haplotype and SCS. Combined genotype EFCDBB and GGEFDD with the lowest SCS were favorable for the mastitis resistance. They may be used as a possible candidate for marker-assisted selection in dairy cattle breeding program.     

Therapeutic Effect of Intravenous Infusion of Perfluorocarbon Emulsion on LPS-Induced Acute Lung Injury in Rats

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) are the leading causes of death in critical care. Despite extensive efforts in research and clinical medicine, mortality remains high in these diseases. Perfluorocarbon (PFC), a chemical compound known as liquid ventilation medium, is capable of dissolving large amounts of physiologically important gases (mainly oxygen and carbon dioxide). In this study we aimed to investigate the effect of intravenous infusion of PFC emulsion on lipopolysaccharide (LPS) induced ALI in rats and elucidate its mechanism of action. Forty two Wistar rats were randomly divided into three groups: 6 rats were treated with saline solution by intratracheal instillation (control group), 18 rats were treated with LPS by intratracheal instillation (LPS group) and the other 18 rats received PFC through femoral vein prior to LPS instillation (LPS+PFC group). The rats in the control group were sacrificed 6 hours later after saline instillation. At 2, 4 and 6 hours of exposure to LPS, 6 rats in the LPS group and 6 rats in LPS+PFC group were sacrificed at each time point. By analyzing pulmonary pathology, partial pressure of oxygen in the blood (PaO2) and lung wet-dry weight ratio (W/D) of each rat, we found that intravenous infusion of PFC significantly alleviated acute lung injury induced by LPS. Moreover, we showed that the expression of pulmonary myeloperoxidase (MPO), intercellular adhesion molecule-1 (ICAM-1) of endothelial cells and CD11b of polymorphonuclear neutrophils (PMN) induced by LPS were significantly decreased by PFC treatment in vivo. Our results indicate that intravenous infusion of PFC inhibits the infiltration of PMNs into lung tissue, which has been shown as the core pathogenesis of ALI/ARDS. Thus, our study provides a theoretical foundation for using intravenous infusion of PFC to prevent and treat ALI/ARDS in clinical practice.     

RNA-dependent dynamic histone acetylation regulates MCL1 alternative splicing

Histone deacetylases (HDACs) and lysine acetyltransferases (KATs) catalyze dynamic histone acetylation at regulatory and coding regions of transcribed genes. Highly phosphorylated HDAC2 is recruited within corepressor complexes to regulatory regions, while the nonphosphorylated form is associated with the gene body. In this study, we characterized the nonphosphorylated HDAC2 complexes recruited to the transcribed gene body and explored the function of HDAC-complex-mediated dynamic histone acetylation. HDAC1 and 2 were coimmunoprecipitated with several splicing factors, including serine/arginine-rich splicing factor 1 (SRSF1) which has roles in alternative splicing. The co-chromatin immunoprecipitation of HDAC1/2 and SRSF1 to the gene body was RNA-dependent. Inhibition of HDAC activity and knockdown of HDAC1, HDAC2 or SRSF1 showed that these proteins were involved in alternative splicing of MCL1. HDAC1/2 and KAT2B were associated with nascent pre-mRNA in general and with MCL1 pre-mRNA specifically. Inhibition of HDAC activity increased the occupancy of KAT2B and acetylation of H3 and H4 of the H3K4 methylated alternative MCL1 exon 2 nucleosome. Thus, nonphosphorylated HDAC1/2 is recruited to pre-mRNA by splicing factors to act at the RNA level with KAT2B and other KATs to catalyze dynamic histone acetylation of the MCL1 alternative exon and alter the splicing of MCL1 pre-mRNA.     

四种中草药对大鼠半乳糖性白内障氧化还原物质及糖类含量的影响

对正常和半乳糖性白内障及给中草药的大鼠晶状体中某些吡啶核苷酸成分、糖类、非蛋白质巯基的含量进行了比较。结果表明,在白内障晶状体中,NADPH及非蛋白质巯基的含量明显低于正常晶状体的,而NADP、半乳糖及半乳糖醇的含量明显高于正常晶状体的;当注射半乳糖的同时分别用黄岑、石斛、菟丝子及玉蝴蝶四种中草药水煎剂灌胃,上述变化为基本恢复至正常晶状体的水平。表明四种中草药对晶状体中的异常生化变化具有阻止及纠正作用。     

Characterization of the role of full-length CRMP3 and its calpain-cleaved product in inhibiting microtubule polymerization and neurite outgrowth

Collapsin response mediator proteins (CRMPs) are key modulators of cytoskeletons during neurite outgrowth in response to chemorepulsive guidance molecules. However, their roles in adult injured neurons are not well understood. We previously demonstrated that CRMP3 underwent calcium-dependent N-terminal protein cleavage during excitotoxicity-induced neurite retraction and neuronal death. Here, we report findings that the full-length CRMP3 inhibits tubulin polymerization and neurite outgrowth in cultured mature cerebellar granule neurons, while the N-terminal truncated CRMP3 underwent nuclear translocation and caused a significant nuclear condensation. The N-terminal truncated CRMP3 underwent nuclear translocation through nuclear pores. Nuclear protein pull-down assay and mass spectrometry analysis showed that the N-terminal truncated CRMP3 was associated with nuclear vimentin. In fact, nuclear-localized CRMP3 co-localized with vimentin during glutamate-induced excitotoxicity. However, the association between the truncated CRMP3 and vimentin was not critical for nuclear condensation and neurite outgrowth since over-expression of truncated CRMP3 in vimentin null neurons did not alleviate nuclear condensation and neurite outgrowth inhibition. Together, these studies showed CRMP3's role in attenuating neurite outgrowth possibility through inhibiting microtubule polymerization, and also revealed its novel association with vimentin during nuclear condensation prior to neuronal death.     

Genomic data reject the hypothesis of a prosimian primate clade

The phylogenetic position of tarsiers within the primates has been a controversial subject for over a century. Despite numerous morphological and molecular studies, there has been weak support for grouping tarsiers with either strepsirrhine primates in a prosimian clade or with anthropoids in a haplorrhine clade. Here, we take advantage of the recently released whole genome assembly of the Philippine tarsier, Tarsius syrichta, in order to infer the phylogenetic relationship of Tarsius within the order Primates. We also present estimates of divergence times within the primates. Using a 1.26 million base pair multiple sequence alignment derived from 1078 orthologous genes, we provide overwhelming statistical support for the presence of a haplorrhine clade. We also present divergence date estimates using local relaxed molecular clock methods. The estimated time of the most recent common ancestor of extant Primates ranged from 64.9 Ma to 72.6 Ma, and haplorrhines were estimated to have a most recent common ancestor between 58.9 Ma and 68.6 Ma. Examination of rates of nucleotide substitution in the three major extant primate clades show that anthropoids have a slower substitution rate than either strepsirrhines or tarsiers. Our results provide the framework on which primate morphological, reproductive, and genomic features can be reconstructed in the broader context of mammalian phylogeny.     

A change from phalanx to guerrilla growth form is an effective strategy to acclimate to sedimentation in a wetland sedge species Carex brevicuspis (Cyperaceae)

The rhizomatous sedge Carex brevicuspis can produce clumping ramets from shortened rhizomes (phalanx) and spreading ramets from elongated rhizomes (guerrilla) to form a combined clonal growth form. In this paper, changes in clonal growth and biomass allocation pattern of C. brevicuspis in response to sedimentation were studied. Four sedimentation depths (0, 3, 6, and 9 cm) were applied to 48 ramets in a randomized block design. Plants were harvested after 20 weeks. With increasing sedimentation depth, the proportion of spreading ramets to total ramets increased from 19.6% in 0 cm to 92.9% in 9 cm sedimentation treatments, whereas that of clumping ramets decreased from 80.4% to 7.1%, indicating a change of clonal growth form from phalanx to guerrilla as a response to sedimentation. With increasing sedimentation depth, biomass allocation to shoots and roots did not change, but rhizome mass ratio increased from 2.7% in 0 cm to 7.2% in 9 cm sedimentation treatments, suggesting that production of long rhizomes changes biomass allocation pattern. The results show that plasticity of clonal growth forms, by which more spreading ramets are produced, is an effective strategy to avoid sedimentation stress under our experimental conditions.     

在大肠杆菌中人腺病毒5型及昆虫核多角体病毒晚期启动子表达CAT基因

本文证明,含有人5型腺病毒及苜蓿丫纹夜蛾核型多角体病毒(AutograPha californica Nuclear Polyhedrosis Virus, AcNPV)启动子的DNA片段,可在大肠杆菌中起始氯霉素乙酰基转移酶(Chloramphenicol Acetyltransferase,CAT)基因的转录和表达,使转化宿主菌表现为氯霉素抗性型。这说明,除痘苗病毒启动子外,其它人类病毒及昆虫病毒的启动子也能有效地在大肠杆菌中工作。