scholarly journals In Vitro Processing of the 3′-Overhanging DNA in the Postcleavage Complex Involved in V(D)J Joining

2004 ◽  
Vol 24 (9) ◽  
pp. 3692-3702 ◽  
Author(s):  
Tadashi Nishihara ◽  
Fumikiyo Nagawa ◽  
Hirofumi Nishizumi ◽  
Masami Kodama ◽  
Satoshi Hirose ◽  
...  
Keyword(s):  
Physiological Role ◽  
Full Length ◽  
Strand Transfer ◽  
The Core ◽  
Transfer Activity ◽  
In Vitro Processing ◽  
Processing Activity

ABSTRACT The postcleavage complex involved in V(D)J joining is known to possess a transpositional strand transfer activity, whose physiological role is yet to be clarified. Here we report that RAG1 and RAG2 proteins in the signal end (SE) complex cleave the 3′-overhanging structure of the synthetic coding-end (CE) DNA in two successive steps in vitro. The 3′-overhanging structure is attacked by the SE complex imprecisely, near the double-stranded/single-stranded (ds/ss) junction, and transferred to the SE. The transferred overhang is then resolved and cleaved precisely at the ds/ss junction, generating either the linear or the circular cleavage products. Thus, the blunt-end structure is restored for the SE and variably processed ends are generated for the synthetic CE. This 3′-processing activity is observed not only with the core RAG2 but also with the full-length protein.

Accurate and efficient 3' processing of U2 small nuclear RNA precursor in a fractionated cytoplasmic extract

1987 ◽  
Vol 7 (9) ◽  
pp. 3131-3137
Author(s):  
A M Kleinschmidt ◽  
T Pederson
Keyword(s):  
Rna Polymerase Ii ◽  
Small Nuclear Rna ◽  
Rnase Protection ◽  
In Vitro Processing ◽  
S100 Extract ◽  
Processing Activity ◽  
Precursor Molecules ◽  
Trna Precursor ◽  
Rna Precursor

The small nuclear RNAs U1, U2, U4, and U5 are cofactors in mRNA splicing and, like the pre-mRNAs with which they interact, are transcribed by RNA polymerase II. Also like mRNAs, mature U1 and U2 RNAs are generated by 3' processing of their primary transcripts. In this study we have investigated the in vitro processing of an SP6-transcribed human U2 RNA precursor, the 3' end of which matches that of authentic human U2 RNA precursor molecules. Although the SP6-U2 RNA precursor was efficiently processed in an ammonium sulfate-fractionated HeLa cytoplasmic S100 extract, the product RNA was unstable. Further purification of the processing activity on glycerol gradients resolved a 7S activity that nonspecifically cleaved all RNAs tested and a 15S activity that efficiently processed the 3' end of pre-U2 RNA. The 15S activity did not process the 3' end of a tRNA precursor molecule. As demonstrated by RNase protection, the processed 3' end of the SP6-U2 RNA maps to the same nucleotides as does mature HeLa U2 RNA.

scholarly journals Screening of the NIH Clinical Collection for inhibitors of HIV-1 integrase activity

2018 ◽  
Vol 114 (3/4) ◽  
Author(s):  
Shaakira Abrahams ◽  
Salerwe Mosebi ◽  
Muhammed Q. Fish ◽  
Maria A. Papathanasopoulos ◽  
Raymond Hewer
Keyword(s):  
Unmet Need ◽  
Epigallocatechin Gallate ◽  
Drug Repurposing ◽  
Strand Transfer ◽  
Vast Number ◽  
Drug Candidates ◽  
Transfer Activity ◽  
Ic50 Values ◽  
Hiv 1

Drug repurposing offers a validated approach to reduce drug attrition within the drug discovery and development pipeline through the application of known drugs and drug candidates to treat new indications. Full exploitation of this strategy necessitates the screening of a vast number of molecules against an extensive number of diseases of high burden or unmet need and the subsequent dissemination of the findings. In order to contribute to endeavours within this field, we screened the 727 compounds comprising the US National Institutes of Health (NIH) Clinical Collection through an HIV-1 (human immunodeficiency virus type 1) integrase stand transfer inhibition assay on an automated scintillation proximity assay platform. Only two compounds were identified within the initial screen, with cefixime trihydrate and epigallocatechin gallate found to reduce integrase strand transfer activity at IC50 values of 6.03±1.29 μM and 9.57±1.62 μM, respectively. However, both cefixime trihydrate and epigallocatechin gallate retained their low micromolar inhibitory activity when tested against a raltegravir-resistant integrase double mutant (FCIC50 values of 0.83 and 0.06, respectively), were ineffective in an orthogonal strand transfer ELISA (less than 30% inhibition at 100 μM) and produced negligible selectivity index values (less than 1) in vitro. While no useful inhibitors of HIV-1 integrase strand transfer activity were found within the NIH Clinical Collection, the identification of two assay-disrupting molecules demonstrates the importance of consideration of non-specific inhibitors in drug repurposing screens.

scholarly journals Coupling of Termination, 3′ Processing, and mRNA Export

2002 ◽  
Vol 22 (18) ◽  
pp. 6441-6457 ◽  
Author(s):  
C. M. Hammell ◽  
Stefan Gross ◽  
Daniel Zenklusen ◽  
Catherine V. Heath ◽  
Francoise Stutz ◽  
...  
Keyword(s):  
Mrna Export ◽  
Mrna Processing ◽  
Nonpermissive Temperature ◽  
Pol Ii ◽  
The Core ◽  
In Vitro Processing ◽  
Novel Alleles ◽  
Processing Factors

ABSTRACT In a screen to identify genes required for mRNA export in Saccharomyces cerevisiae, we isolated an allele of poly(A) polymerase (PAP1) and novel alleles encoding several other 3′ processing factors. Many newly isolated and some previously described mutants (rna14-48, rna14-49, rna14-64, rna15-58, and pcf11-1 strains) are defective in polymerase II (Pol II) termination but, interestingly, retain the ability to polyadenylate these improperly processed transcripts at the nonpermissive temperature. Deletion of the cis-acting sequences required to couple 3′ processing and termination also produces transcripts that fail to exit the nucleus, suggesting that all of these processes (cleavage, termination, and export) are coupled. We also find that several but not all mRNA export mutants produce improperly 3′ processed transcripts at the nonpermissive temperature. 3′ maturation defects in mRNA export mutants include improper Pol II termination and/or the previously characterized hyperpolyadenylation of transcripts. Importantly, not all mRNA export mutants have defects in 3′ processing. The similarity of the phenotypes of some mRNA export mutants and 3′ processing mutants indicates that some factors from each process may mechanistically interact to couple mRNA processing and export. Consistent with this assumption, we present evidence that Xpo1p interacts in vivo with several 3′ processing factors and that the addition of recombinant Xpo1p to in vitro processing reaction mixtures stimulates 3′ maturation. Of the core 3′ processing factors tested (Rna14p, Rna15p, Pcf11p, Hrp1p, Fip1p, and Cft1p), only Hrp1p shuttles. Overexpression of Rat8p/Dbp5p suppresses both 3′ processing and mRNA export defects found in xpo1-1 cells.

scholarly journals Composition and processing activity of a semi-recombinant holo U7 snRNP

2019 ◽  
Vol 48 (3) ◽  
pp. 1508-1530 ◽  
Author(s):  
Katarzyna Bucholc ◽  
Wei Shen Aik ◽  
Xiao-cui Yang ◽  
Kaituo Wang ◽  
Z Hong Zhou ◽  
...  
Keyword(s):  
Animal Cells ◽  
Sm Proteins ◽  
Nuclear Extracts ◽  
In Vitro Processing ◽  
Functionally Impaired ◽  
Catalytically Active ◽  
U7 Snrnp ◽  
Core Components ◽  
Processing Activity

Abstract In animal cells, replication-dependent histone pre-mRNAs are cleaved at the 3′ end by U7 snRNP consisting of two core components: a ∼60-nucleotide U7 snRNA and a ring of seven proteins, with Lsm10 and Lsm11 replacing the spliceosomal SmD1 and SmD2. Lsm11 interacts with FLASH and together they recruit the endonuclease CPSF73 and other polyadenylation factors, forming catalytically active holo U7 snRNP. Here, we assembled core U7 snRNP bound to FLASH from recombinant components and analyzed its appearance by electron microscopy and ability to support histone pre-mRNA processing in the presence of polyadenylation factors from nuclear extracts. We demonstrate that semi-recombinant holo U7 snRNP reconstituted in this manner has the same composition and functional properties as endogenous U7 snRNP, and accurately cleaves histone pre-mRNAs in a reconstituted in vitro processing reaction. We also demonstrate that the U7-specific Sm ring assembles efficiently in vitro on a spliceosomal Sm site but the engineered U7 snRNP is functionally impaired. This approach offers a unique opportunity to study the importance of various regions in the Sm proteins and U7 snRNA in 3′ end processing of histone pre-mRNAs.

scholarly journals Characterization of a Replication-Defective Human Immunodeficiency Virus Type 1 att Site Mutant That Is Blocked after the 3′ Processing Step of Retroviral Integration

2000 ◽  
Vol 74 (17) ◽  
pp. 8188-8193 ◽  
Author(s):  
Hongmin Chen ◽  
Alan Engelman
Keyword(s):  
Strand Transfer ◽  
Retroviral Integration ◽  
Transfer Activity ◽  
Processing Step ◽  
Immunodeficiency Virus ◽  
Viral Cdna ◽  
Dna Strand

ABSTRACT Two activities of retroviral integrase, 3′ processing and DNA strand transfer, are required to integrate viral cDNA into a host cell chromosome. Integrase activity has been analyzed in vitro using purified protein and recombinant DNA substrates that model the U3 and U5 ends of viral cDNA or by using viral preintegration complexes (PICs) that form during virus infection. Numerous studies have investigated changes in integrase or viral DNA for effects on both 3′ processing and DNA strand transfer activities using purified protein, but similar analyses have not been carried out using PICs. Here, we analyzed PICs from human immunodeficiency virus type 1 (HIV-1) strain 604del, an integration-defective mutant lacking 26 bp of U5, and revE1, a revertant of 604del containing an additional 19-bp deletion, for levels of 3′ processing activity that occurred in infected cells and for levels of in vitro DNA strand transfer activity. Whereas revE1 supported one-third to one-half of the level of wild-type DNA strand transfer activity, the level of 604del DNA strand transfer activity was undetectable. Surprisingly, integrase similarly processed the 3′ ends of 604del and revE1 in vivo. We therefore conclude that 604del is blocked in its ability to replicate in cells after the 3′ processing step of retroviral integration. Whereas Western blotting showed that wild-type, revE1, and 604del PICs contained similar levels of integrase protein, Mu-mediated PCR footprinting revealed only minimal protein-DNA complex formation at the ends of 604del cDNA. We propose that 604del is replication defective because proteins important for DNA strand transfer activity do not stably associate with this cDNA after in vivo 3′ processing by integrase.

scholarly journals Characterization of a Novel Isoform of Caspase-9 That Inhibits Apoptosis

2001 ◽  
Vol 276 (15) ◽  
pp. 12190-12200 ◽  
Author(s):  
James M. Angelastro ◽  
Nah Yong Moon ◽  
David X. Liu ◽  
An-Suei Yang ◽  
Lloyd A. Greene ◽  
...  
Keyword(s):  
Cell Death ◽  
Physiological Role ◽  
Neuronal Cell ◽  
Cell Types ◽  
Dominant Negative ◽  
Full Length ◽  
Peptide Sequence ◽  
Caspase 9 ◽  
Dominant Negative Variant

We have identified a novel isoform of rat caspase-9 in which the C terminus of full-length caspase-9 is replaced with an alternative peptide sequence. Casp-9-CTD (where CTD is carboxyl-terminal divergent) is expressed in multiple tissues, with the relative highest expression observed in ovary and heart. Casp-9-CTD was found primarily in the cytoplasm and was not detected in the nucleus. Structural predictions suggest that in contrast to full-length caspase-9, casp-9-CTD will not be processed. Our model is supported by reduced protease activity of casp-9-CTD preparationsin vitroand by the lack of detectable processing of casp-9-CTD proenzyme or the induction of cell death following transfection into cells. Both neuronal and non-neuronal cell types transfected with casp-9-CTD were resistant to death evoked by trophic factor deprivation or DNA damage. In addition, cytosolic lysates prepared from cells permanently expressing exogenous casp-9-CTD were resistant to caspase induction by cytochromecin reconstitution assays. Taken together, our observations indicate that casp-9-CTD acts as a dominant-negative variant. Its expression in various tissues indicates a physiological role in regulating cell death.

scholarly journals Accurate and efficient 3' processing of U2 small nuclear RNA precursor in a fractionated cytoplasmic extract.

1987 ◽  
Vol 7 (9) ◽  
pp. 3131-3137 ◽  
Author(s):  
A M Kleinschmidt ◽  
T Pederson
Keyword(s):  
Rna Polymerase Ii ◽  
Small Nuclear Rna ◽  
Rnase Protection ◽  
In Vitro Processing ◽  
S100 Extract ◽  
Processing Activity ◽  
Precursor Molecules ◽  
Trna Precursor ◽  
Rna Precursor

The small nuclear RNAs U1, U2, U4, and U5 are cofactors in mRNA splicing and, like the pre-mRNAs with which they interact, are transcribed by RNA polymerase II. Also like mRNAs, mature U1 and U2 RNAs are generated by 3' processing of their primary transcripts. In this study we have investigated the in vitro processing of an SP6-transcribed human U2 RNA precursor, the 3' end of which matches that of authentic human U2 RNA precursor molecules. Although the SP6-U2 RNA precursor was efficiently processed in an ammonium sulfate-fractionated HeLa cytoplasmic S100 extract, the product RNA was unstable. Further purification of the processing activity on glycerol gradients resolved a 7S activity that nonspecifically cleaved all RNAs tested and a 15S activity that efficiently processed the 3' end of pre-U2 RNA. The 15S activity did not process the 3' end of a tRNA precursor molecule. As demonstrated by RNase protection, the processed 3' end of the SP6-U2 RNA maps to the same nucleotides as does mature HeLa U2 RNA.

In Situ Localization of PPAR Gamma and Uncoupling Protein in Mouse Embryo Sections Using Digoxigenin-Labeled Riboprobes

1996 ◽  
Vol 54 ◽  
pp. 32-33
Author(s):  
C. Jennermann ◽  
S. A. Kliewer ◽  
D. C. Morris
Keyword(s):  
Alkaline Phosphatase ◽  
Room Temperature ◽  
Uncoupling Protein ◽  
Ppar Gamma ◽  
Nuclear Hormone Receptor ◽  
Full Length ◽  
Northern Analysis ◽  
Peroxisome Proliferator

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.

Repositioning of Difluorinated Propanediones as Inhibitors of Histone Methyltransferases and their Biological Evaluation in Human Leukemic Cell Lines

2019 ◽  
Vol 18 (13) ◽  
pp. 1892-1899 ◽  
Author(s):  
Tanushree Pal ◽  
Asmita Sharda ◽  
Bharat Khade ◽  
C. Sinha Ramaa ◽  
Sanjay Gupta
Keyword(s):  
Cell Lines ◽  
Physiological Role ◽  
Leukemic Cell ◽  
Docking Studies ◽  
Biological Evaluation ◽  
Leukemic Cell Lines ◽  
Histone Lysine ◽  
Histone Lysine Methyltransferase ◽  
Subsequent Decrease

Background: At present, ‘pharmaco-epigenomics’ constitutes the hope in cancer treatment owing to epigenetic deregulation- a reversible process and playing a role in malignancy. Objective: Chemotherapy has many limitations like host-tissue toxicity, drug resistance. Hence, it is imperative to unearth targets to better treat cancer. Here, we intend to repurpose a set of our previously synthesized difluorinated Propanediones (PR) as Histone lysine Methyltransferase inhibitors (HMTi). Methods: The cell lines of leukemic origin viz. histiocytic lymphoma (U937) and acute T-cell leukemia (JURKAT) were treated with PR-1 to 7 after docking studies with active pocket of HMT. The cell cycle analysis, in vitro methylation and cell proliferation assays were carried out to delineate their physiological role. Results: A small molecule PR-4, at 1 and 10µM, has shown to alter the methylation of histone H3 and H4 in both cell lines. Also, treatment shows an increase in G2/M population and a subsequent decrease in the G0/G1 population in U937. In JURKAT, an increase in both G2/M and S phase population was observed. The sub-G1 population showed a steady rise with increase in dose and prolonged time intervals in U937 and JURKAT cell lines. In SRB assay, the PR showed a cell growth of 42.6 and 53.4% comparable to adriamycin; 44.5 and 53.2% in U937 and JURKAT, respectively. The study suggests that PR-4 could emerge as a potential HMT inhibitor. Conclusion: The molecule PR-4 could be a lead in developing more histone lysine methyltransferases inhibitors with potential to be pro-apoptotic agents.

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