Characterization of cleavage and polyadenylation specificity factor and cloning of its 100-kilodalton subunit

1994 ◽  
Vol 14 (12) ◽  
pp. 8183-8190
Author(s):  
A Jenny ◽  
H P Hauri ◽  
W Keller

During the formation of the 3' ends of mRNA, the cleavage and polyadenylation specificity factor (CPSF) is required for 3' cleavage of the transcript as well as for subsequent polyadenylation. Using peptide sequences from a tryptic digest, we have cloned the 100-kDa subunit of CPSF. This subunit is a novel protein showing no homology to any known polypeptide in databases. Polyclonal antibodies against the C terminus of the protein inhibit the polyadenylation reaction. Polyclonal and monoclonal antibodies were used to characterize the composition of CPSF. Immunoprecipitations of CPSF from HeLa cell extracts and from labeled chromatographic fractions show the coprecipitation of all four subunits of 160, 100, 73, and 30 kDa. Proteins of 160 and 30 kDa that are specifically cross-linked to precursor RNA by UV irradiation were identified as CPSF subunits by immunoprecipitation. Immunofluorescent detection of CPSF in HeLa cells localized it in the nucleoplasm, excluding cytoplasm and nucleolar structures.

1994 ◽  
Vol 14 (12) ◽  
pp. 8183-8190 ◽  
Author(s):  
A Jenny ◽  
H P Hauri ◽  
W Keller

During the formation of the 3' ends of mRNA, the cleavage and polyadenylation specificity factor (CPSF) is required for 3' cleavage of the transcript as well as for subsequent polyadenylation. Using peptide sequences from a tryptic digest, we have cloned the 100-kDa subunit of CPSF. This subunit is a novel protein showing no homology to any known polypeptide in databases. Polyclonal antibodies against the C terminus of the protein inhibit the polyadenylation reaction. Polyclonal and monoclonal antibodies were used to characterize the composition of CPSF. Immunoprecipitations of CPSF from HeLa cell extracts and from labeled chromatographic fractions show the coprecipitation of all four subunits of 160, 100, 73, and 30 kDa. Proteins of 160 and 30 kDa that are specifically cross-linked to precursor RNA by UV irradiation were identified as CPSF subunits by immunoprecipitation. Immunofluorescent detection of CPSF in HeLa cells localized it in the nucleoplasm, excluding cytoplasm and nucleolar structures.


2013 ◽  
Vol 47 (2) ◽  
pp. 128-137 ◽  
Author(s):  
Sendi Montanic ◽  
Michela Terdoslavich ◽  
Uros Rajcevic ◽  
Luigina De Leo ◽  
Serena Department of Medical Sciences, Uni ◽  
...  

Background. Bilitranslocase (TC 2.A.65.1.1) is a bilirubin-specific membrane transporter, found on absorptive (stomach and intestine) and excretory (kidney and liver) epithelia and in vascular endothelium. Polyclonal antibodies have been raised in rabbits in the past, using a synthetic peptide corresponding to AA65-77 of rat liver bilitranslocase, as an antigen. Affinity-purified antibodies from immune sera have been found to inhibit various membrane transport functions, including the bilirubin uptake into human hepatocytes and the uptake of some flavonoids into human vascular endothelial cells. It was described by means of immunohistochemistry using polyclonal antibodies that bilitranslocase expression is severely down-regulated in clear cell renal carcinoma. The aim of our work was development and characterization of high-affinity, specific mAbs against bilitranslocase, which can be used as a potential diagnostic tool in renal cell carcinoma as well as in a wide variety of biological assays on different human tissues. Materials and methods. Mice were immunized with a multi-antigen peptide corresponding to segment 65-75 of predicted primary structure of the bilitranslocase protein. By a sequence of cloning, immune- and functional tests, we aimed at obtaining a specific monoclonal antibody which recognizes a 37 kDa membrane protein, and influences the transport activity of bilitranslocase. Results. On the basis of previous results, specific IgM monoclonal antibodies were produced in BALB/c mice, in order to further improve and extend the immunological approach to the study of bilitranslocase in renal cancer cells as well as to develop its potential diagnostics use. Conclusions. In this article we show an immunological approach, based on newly developed monoclonal antibodies, to a detailed biochemical and functional characterization of a protein whose gene and protein structure is still unknown. We were able to demonstrate our novel mAb as a tumor marker candidate of renal cell carcinoma, which may prove useful in the diagnostic procedures.


2014 ◽  
Author(s):  
Alessandro Didonna ◽  
Anja Colja Venturini ◽  
Katrina Hartman ◽  
Tanja Vranac ◽  
Vladka Curin Serbec ◽  
...  

Prion diseases are a group of fatal neurodegenerative disorders that affect humans and animals. They are characterized by the accumulation in the central nervous system of a pathological form of the host-encoded prion protein (PrPC). The prion protein is a membrane glycoprotein that consists of two domains: a globular, structured C-terminus and an unstructured N-terminus. The N-terminal part of the protein is involved in different functions in both health and disease. In the present work we discuss the production and biochemical characterization of a panel of four monoclonal antibodies (mAbs) against the distal N-terminus of PrPC using a well-established methodology based on the immunization of Prnp0/0 mice. Additionally, we show their ability to block prion (PrPSc) replication at nanomolar concentrations in a cell culture model of prion infection. These mAbs represent a promising tool for prion diagnostics and for studying the physiological role of the N-terminal domain of PrPC.


1997 ◽  
Vol 327 (2) ◽  
pp. 481-486 ◽  
Author(s):  
Susanne KLOEKER ◽  
C. Jeffrey BRYANT ◽  
Stefan STRACK ◽  
J. Roger COLBRAN ◽  
E. Brian WADZINSKI

Specific rabbit polyclonal antibodies against peptides corresponding to the highly homologous protein serine/threonine phosphatase 2A and X catalytic subunits (PP2A/C and PPX/C respectively) were used to investigate the cellular and subcellular distribution of PP2A/C and PPX/C, as well as their methylation state. Immunoblots of rat tissue extracts revealed a widespread distribution of these enzymes but particularly high levels of PP2A/C and PPX/C in brain and testes respectively. In addition, immunoblots of subcellular fractions and immunocytochemical analyses of rat brain sections demonstrated that PPX/C is predominantly localized to the nucleus, whereas PP2A/C is largely cytoplasmic. Treatment of nuclear extracts with alkali resulted in increased PPX/C immunoreactivity to a polyclonal antibody directed against the C-terminus; no change in PPX immunoreactivity was observed using an antibody against an internal peptide. Alkali treatment of brain and liver cytosolic and nuclear extracts did not change the molecular mass or the isoelectric point of PPX/C. Furthermore, tritiated PPX/C was immunoprecipitated from COS cell extracts incubated with the methyl donor S-adenosyl-l-[methyl-3H]methionine. Thus the increase in immunoreactivity probably results from removal of a carboxymethyl group from PPX/C, as has been shown previously for PP2A/C [Favre, Zolnierowicz, Turowski and Hemmings (1994) J. Biol. Chem. 269, 16311-16317]. Together, our results indicate that the PPX catalytic subunit is a predominantly nuclear phosphatase and is methylated at its C-terminus.


2007 ◽  
Vol 81 (17) ◽  
pp. 8989-8995 ◽  
Author(s):  
Zhaochun Chen ◽  
Patricia Earl ◽  
Jeffrey Americo ◽  
Inger Damon ◽  
Scott K. Smith ◽  
...  

ABSTRACT Three distinct chimpanzee Fabs against the A33 envelope glycoprotein of vaccinia virus were isolated and converted into complete monoclonal antibodies (MAbs) with human γ1 heavy-chain constant regions. The three MAbs (6C, 12C, and 12F) displayed high binding affinities to A33 (Kd of 0.14 nM to 20 nM) and may recognize the same epitope, which was determined to be conformational and located within amino acid residues 99 to 185 at the C terminus of A33. One or more of the MAbs were shown to reduce the spread of vaccinia virus as well as variola virus (the causative agent of smallpox) in vitro and to more effectively protect mice when administered before or 2 days after intranasal challenge with virulent vaccinia virus than a previously isolated mouse anti-A33 MAb (1G10) or vaccinia virus immunoglobulin. The protective efficacy afforded by anti-A33 MAb was comparable to that of a previously isolated chimpanzee/human anti-B5 MAb. The combination of anti-A33 MAb and anti-B5 MAb did not synergize the protective efficacy. These chimpanzee/human anti-A33 MAbs may be useful in the prevention and treatment of vaccinia virus-induced complications of vaccination against smallpox and may also be effective in the immunoprophylaxis and immunotherapy of smallpox and other orthopoxvirus diseases.


2021 ◽  
Author(s):  
Aleksandar Antanasijevic ◽  
Charles A. Bowman ◽  
Robert N. Kirchdoerfer ◽  
Cristopher A. Cottrell ◽  
Gabriel Ozorowski ◽  
...  

One of the rate-limiting steps in analyzing immune responses to vaccines or infections is the isolation and characterization of monoclonal antibodies. Here, we present a hybrid structural and bioinformatic approach to directly assign the heavy and light chains, identify complementarity- determining regions and discover sequences from cryoEM density maps of serum-derived polyclonal antibodies bound to an antigen. When combined with next generation sequencing of immune repertoires we were able to specifically identify clonal family members, synthesize the monoclonal antibodies and confirm that they interact with the antigen in a manner equivalent to the corresponding polyclonal antibodies. This structure-based approach for identification of monoclonal antibodies from polyclonal sera opens new avenues for analysis of immune responses and iterative vaccine design.


1998 ◽  
Vol 64 (12) ◽  
pp. 5033-5038 ◽  
Author(s):  
N. de Vries ◽  
K. A. Zwaagstra ◽  
J. H. J. Huis in’t Veld ◽  
F. van Knapen ◽  
F. G. van Zijderveld ◽  
...  

ABSTRACT Salmonella typhimurium expresses two antigenically distinct flagellins, each containing a different H antigen (i and 1,2), the combination of which is highly specific for this serotype. In this study, overlapping recombinant flagellin fragments were constructed from the fliC(H:i) and fljB (H:1,2) flagellin genes, and the expression products were tested for binding to H antigen-specific monoclonal and polyclonal antibodies. A minimal area, 86 amino acids for H:i and 102 amino acids for H:1,2, located in the central variable domain of each flagellin was required for the binding of serotype-specific antibodies, providing further evidence for the presence of a discontinuous H epitope. Two peptides comprising these areas were shown to be highly suitable for application as antigens in an enzyme-linked immunosorbent assay detecting S. typhimurium-specific antibody.


1996 ◽  
Vol 16 (4) ◽  
pp. 1391-1400 ◽  
Author(s):  
T Kiss ◽  
M L Bortolin ◽  
W Filipowicz

We have characterized a new member (U19) of a group of mammalian small nuclear RNAs that are not precipitable with antibodies against fibrillarin, a conserved nucleolar protein associated with most of the small nucleolar RNAs characterized to date. Human U19 RNA is 200 nucleotides long and possesses 5'-monophosphate and 3'-hydroxyl termini. It lacks functional boxes C and D, sequence motifs required for fibrillarin binding in many other snoRNAs. Human and mouse RNA are 86% homologous and can be folded into similar secondary structures, a finding supported by the results of nuclease probing of the RNA. In the human genome, U19 RNA is encoded in the intron of an as yet not fully characterized gene and could be faithfully processed from a longer precursor RNA in HeLa cell extracts. During fractionation of HeLa cell nucleolar extracts on glycerol gradients, U19 RNA was associated with higher-order structures of approximately 65S, cosedimenting with complexes containing 7-2/MRP RNA, a conserved nucleolar RNA shown to be involved in 5.8S rRNA processing in yeast cells.


2006 ◽  
Vol 80 (3) ◽  
pp. 1604-1609 ◽  
Author(s):  
Yuko Yoto ◽  
Jianming Qiu ◽  
David J. Pintel

ABSTRACT Polyadenylation of B19 pre-mRNAs at the major internal site, (pA)p1, is programmed by the nonconsensus core cleavage and polyadenylation specificity factor-binding hexanucleotide AUUAAA. Efficient use of this element requires both downstream and upstream cis-acting elements and is further influenced by an adjacent AAUAAC motif. The primary hexanucleotide element must be nonconsensus to allow efficient readthrough of P6-generated pre-mRNAs into the capsid-coding region. An additional cleavage and polyadenylation site, (pA)p2, 296 nucleotides downstream of (pA)p1 was shown to be used following both B19 infection and transfection of a genomic clone. RNAs polyadenylated at (pA)p2 comprise approximately 10% of B19 RNAs that are polyadenylated internally.


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