Molecular cloning and sequence analysis of cystatin from rainbow trout (Oncorhynchus mykiss)

A partial cystatin cDNA from rainbow trout was generated by reverse transcription polymerase chain reaction with two degenerate primers. The partial cystatin PCR product was 168 bp and used to screen trout liver λgt 11 cDNA library. Four positive clones were isolated and designated as cstl, cst2, cst3 and cst4. Only cst2 contained the full-length cystatin cDNA which was 674 bp and included 5' untranslated region and the polyadenylation signal sequence AATAAA in the 3' region. Translation of the cDNA contains 132 amino acid residues. Comparison of the amino acid sequence with those of family II cystatin indicated that the 21 amino acids at N-terminal end is a signal peptide that leads to cystatin secretion, and the 111 amino acids are mature cystatin. Four cysteine residues in the cystatin may form two disulfide bonds for the secondary structure. Cst2 was subcloned into pGEM-3z for Northern and Southern blot experiments. Northern blot indicated that trout cystatin mRNA is about 750 bp. Cystatin is expressed in all tissues examined but at various levels. This difference may reflect the regulation of cysteine proteinase activities. Southern blot of trout genomic DNA showed that the copy number of the trout cystatin gene is probably one per haploid genome

A β-glucosidase hyper-production Trichoderma reesei mutant reveals a potential role of cel3D in cellulase production

Abstract Background The conversion of cellulose by cellulase to fermentable sugars for biomass-based products such as cellulosic biofuels, biobased fine chemicals and medicines is an environment-friendly and sustainable process, making wastes profitable and bringing economic benefits. Trichoderma reesei is the well-known major workhorse for cellulase production in industry, but the low β-glucosidase activity in T. reesei cellulase leads to inefficiency in biomass degradation and limits its industrial application. Thus, there are ongoing interests in research to develop methods to overcome this insufficiency. Moreover, although β-glucosidases have been demonstrated to influence cellulase production and participate in the regulation of cellulase production, the underlying mechanism remains unclear. Results The T. reesei recombinant strain TRB1 was constructed from T. reesei RUT-C30 by the T-DNA-based mutagenesis. Compared to RUT-C30, TRB1 displays a significant enhancement of extracellular β-glucosidase (BGL1) activity with 17-fold increase, a moderate increase of both the endoglucanase (EG) activity and the exoglucanase (CBH) activity, a minor improvement of the total filter paper activity, and a faster cellulase induction. This superiority of TRB1 over RUT-C30 is independent on carbon sources and improves the saccharification ability of TRB1 cellulase on pretreated corn stover. Furthermore, TRB1 shows better resistance to carbon catabolite repression than RUT-C30. Secretome characterization of TRB1 shows that the amount of CBH, EG and BGL in the supernatant of T. reesei TRB1 was indeed increased along with the enhanced activities of these three enzymes. Surprisingly, qRT-PCR and gene cloning showed that in TRB1 β-glucosidase cel3D was mutated through the random insertion by AMT and was not expressed. Conclusions The T. reesei recombinant strain TRB1 constructed in this study is more desirable for industrial application than the parental strain RUT-C30, showing extracellular β-glucosidase hyper production, high cellulase production within a shorter time and a better resistance to carbon catabolite repression. Disruption of β-glucosidase cel3D in TRB1 was identified, which might contribute to the superiority of TRB1 over RUT-C30 and might play a role in the cellulase production. These results laid a foundation for future investigations to further improve cellulase enzymatic efficiency and reduce cost for T. reesei cellulase production.http://deepblue.lib.umich.edu/bitstream/2027.42/134636/1/12934_2016_Article_550.pd

Bis(μ-2-{bis­[(2-oxidobenzyl­idene)amino]­meth­yl}phenolato)bis­[(tetra­hydro­furan)­samarium(III)] tetra­hydro­furan disolvate

In the centrosymmetric binuclear complex of the title solvate, [Sm2(C21H15N2O3)2(C4H8O)2]·2C4H8O, the SmIII is coordin­ated in a distorted monocapped octa­hedral geometry by four O atoms and two N atoms from two tridentate deprotonated 2-{bis­[(2-oxidobenzyl­idene)amino]­meth­yl}phenolate ligands and an O atom of a tetra­hydro­furan (THF) mol­ecule. The Sm⋯Sm distance in the complex is 3.8057 (4) Å. Parts of the coordinating THF mol­ecule are disordered over two sets of sites in a 0.56 (3):0.44 (3) ratio. The complex and solvent mol­ecules are linked into a three-dimensional structure via C—H⋯O hydrogen-bonding inter­actions

Broadly permissive intestinal chromatin underlies lateral inhibition and cell plasticity

Cells differentiate when transcription factors (TFs) bind accessible cis-regulatory elements to establish specific gene expression programs. In differentiating embryonic stem (ES) cells, chromatin at lineage-restricted genes becomes sequentially accessible1-4, probably by virtue of “pioneer” TF activity5, but tissues may utilize other strategies in vivo. Lateral inhibition is a pervasive process in which one cell forces a different identity on its neighbors6, and it is unclear how chromatin in equipotent progenitors undergoing lateral inhibition quickly enables distinct, transiently reversible cell fates. Here we report the chromatin and transcriptional underpinnings of differentiation in mouse small intestine crypts, where Notch signaling mediates lateral inhibition to assign progenitor cells into absorptive or secretory lineages7-9. Transcript profiles in isolated LGR5+ intestinal stem cells (ISC)10 and secretory and absorptive progenitors indicated that each cell population was distinct and the progenitors specified. Nevertheless, secretory and absorptive progenitors showed comparable levels of H3K4me2 and H3K27ac histone marks and DNaseI hypersensitivity - signifying accessible, permissive chromatin - at most of the same cis-elements. Enhancers acting uniquely in progenitors were well-demarcated in LGR5+ ISC, revealing early priming of chromatin for divergent transcriptional programs, and retained active marks well after lineages were specified. On this chromatin background, ATOH1, a secretory-specific TF, controls lateral inhibition through Delta-like Notch ligand genes and also drives numerous secretory lineage genes. Depletion of ATOH1 from specified secretory cells converted them into functional enterocytes, indicating prolonged responsiveness of marked enhancers to presence or absence of a key TF. Thus, lateral inhibition and intestinal crypt lineage plasticity involve interaction of a lineage-restricted TF with broadly permissive chromatin established in multipotent stem cells

Oncogenic Deregulation of EZH2 as an Opportunity for Targeted Therapy in Lung Cancer

As a master regulator of chromatin function, the lysine methyltransferase EZH2 orchestrates transcriptional silencing of developmental gene networks. Overexpression of EZH2 is commonly observed in human epithelial cancers, such as non-small cell lung carcinoma (NSCLC), yet definitive demonstration of malignant transformation by deregulated EZH2 remains elusive. Here, we demonstrate the causal role of EZH2 overexpression in NSCLC with new genetically-engineered mouse models of lung adenocarcinoma. Deregulated EZH2 silences normal developmental pathways leading to epigenetic transformation independent from canonical growth factor pathway activation. As such, tumors feature a transcriptional program distinct from KRAS- and EGFR-mutant mouse lung cancers, but shared with human lung adenocarcinomas exhibiting high EZH2 expression. To target EZH2-dependent cancers, we developed a novel and potent EZH2 inhibitor JQEZ5 that promoted the regression of EZH2-driven tumors in vivo, confirming oncogenic addiction to EZH2 in established tumors and providing the rationale for epigenetic therapy in a subset of lung cancer