scholarly journals Characterization of pinin, a novel protein associated with the desmosome-intermediate filament complex.

1996 ◽  
Vol 135 (4) ◽  
pp. 1027-1042 ◽  
Author(s):  
P Ouyang ◽  
S P Sugrue

We have identified a protein named pinin that is associated with the mature desmosomes of the epithelia (Ouyang, P., and S.P. Sugrue. 1992. J. Cell Biol. 118:1477-1488). We suggest that the function of pinin is to pin intermediate filaments to the desmosome. Therefore, pinin may play a significant role in reinforcing the intermediate filament-desmosome complex. cDNA clones coding for pinin were identified, using degenerative oligonucleotide probes that were based on the internal amino acid sequence of pinin for the screening of a cDNA library. Immunoblotting of expressed recombinant proteins with the monoclonal 08L antibody localized the 08L epitope to the carboxyl end of the protein. Polyclonal antibodies directed against fusion proteins immunoidentified the 140-kD protein in tissue extracts. Immunofluorescence analysis, using the antifusion protein antibody, demonstrated pinin at lateral epithelial boundaries, which is consistent with desmosomal localization. The conceptual translation product of the cDNA clones contained three unique domains: (a) a serine-rich domain; (b) a glutamine-proline, glutamine-leucine repeat domain; and (c) an acidic domain rich in glutamic acid. Although the 3' end of the open reading frame of the clone for pinin showed near identity to a partial cDNA isolated for a pig neutrophil phosphoprotein (Bellavite, P., F. Bazzoni, et al. 1990. Biochem. Biophys. Res. Commun. 170:915-922), the remaining sequence demonstrated little homology to known protein sequences. Northern blots of mRNA from chicken corneal epithelium, MDCK cells, and various human tissues indicated that pinin messages exhibit tissue-specific variation in size, ranging from 3.2 to 4.1 kb. Genomic Southern blots revealed the existence of one gene for pinin, suggesting alternative splicing of the mRNA. Expression of the full-length cDNA clones in human 293 cells and monkey COS-7 cells demonstrated that a 140-kD immunoreactive species on Western blots corresponded to pinin. Pinin cDNA transfected into the transformed 293 cells resulted in enhanced cell-cell adhesion. Immunofluorescence staining revealed that the expressed pinin protein was assembled to the lateral boundaries of the cells in contact, which is consistent with the staining pattern of pinin in epithelial cells.

2003 ◽  
Vol 50 (1) ◽  
pp. 269-278
Author(s):  
Amr M Shabaan ◽  
Magdy M Mohamed ◽  
Mohga S Abdallah ◽  
Hayat M Ibrahim ◽  
Amr M Karim

Two Schistosoma mansoni cDNA clones 30S and 1H were identified by immunoscreening of sporocyst lambdagt11 library and by random sequencing of clones from lambdaZap libraries, respectively. Clone 30S was one of 30 clones identified by an antibody raised against tegument of 3-h schistosomules. The clone was found to encode an 81 amino-acid protein fragment. It was expressed in Escherichia coli as a fusion protein of calculated molecular mass of about 35 kDa with C-terminus of Schistosoma japonicum glutathione-S-transferase (Sj26; about 26 kDa). The recombinant fusion protein was specifically recognized by serum of rabbits immunized with irradiated cercariae. Clone 1H is one of 76 expressed sequence tags derived from an adult worm library. It encodes the complete sequence of a tegumental membrane protein, Sm13. The 104 amino-acid open reading frame encodes a protein with a calculated molecular mass of about 11.9 kDa. Clone 1H was expressed in E. coli as an insoluble fusion protein with Sj26 of about 40 kDa. In Western blots, the fusion protein was recognized by serum from rabbits vaccinated with irradiated cercariae but not by preimmune rabbit sera. The cloning, characterization and expression of those proteins are therefore potentially usefull for vaccine development.


1989 ◽  
Vol 169 (2) ◽  
pp. 481-492 ◽  
Author(s):  
W Kraus ◽  
K Ohyama ◽  
D S Snyder ◽  
E H Beachey

The crossreactivity of antibodies against a renal autoimmune epitope of Streptococcus pyogenes M protein with glomerular mesangial cells was investigated. The antibodies directed against the amino acid sequence Ile-Arg-Leu-Arg of the nephritogenic type 1 M protein reacted in a fibrillar pattern with mesangial cells cultured from isolated glomeruli. In Western blots of urea-extracted mesangial proteins, the antibodies reacted with a 56-kD protein. Monoclonal and polyclonal antibodies identified the 56-kD mesangial protein as vimentin. Two synthetic peptides of human vimentin containing the sequence Arg-Leu-Arg reacted with the autoimmune antibodies raised against a streptococcal M protein peptide. These results provide evidence that the intermediate filament protein vimentin shares autoimmune epitopes with streptococcal M protein.


2008 ◽  
Vol 294 (3) ◽  
pp. R1092-R1102 ◽  
Author(s):  
James B. Claiborne ◽  
Keith P. Choe ◽  
Alison I. Morrison-Shetlar ◽  
Jill C. Weakley ◽  
Justin Havird ◽  
...  

The dogfish ( Squalus acanthias) can make rapid adjustments to gill acid-base transfers to compensate for internal acidosis/alkalosis. Branchial Na+/H+ exchange (NHE) has been postulated as one mechanism driving the excretion of H+ following acidosis. We have cloned gill cDNA that includes an open reading frame coding for a 770-residue protein most homologous (∼71%) to mammalian NHE2. RT-PCR revealed NHE2 transcripts predominantly in gill, stomach, rectal gland, intestine, and kidney. In situ hybridization with an antisense probe against NHE2 in gill sections revealed a strong mRNA signal from a subset of interlamellar and lamellae cells. We developed dogfish-specific polyclonal antibodies against NHE2 that detected a ∼70-kDa protein in Western blots and immunologically recognized branchial cells having two patterns of protein expression. Cytoplasmic and apical NHE2 immunoreactivity were observed in cells coexpressing basolateral Na+-K+-ATPase. Other large ovoid cells more generally staining for NHE2 also were strongly positive for basolateral H+-ATPase. Gill mRNA levels for NHE2 and H+-ATPase did not change following systemic acidosis (as measured by quantitative PCR 2 h after a 1- or 2-meq/kg acid infusion). These data indicate that posttranslational adjustments of NHE2 and other transport systems (e.g., NHE3) following acidosis may be of importance in the short-term pH adjustment and net branchial H+ efflux observed in vivo. NHE2 may play multiple roles in the gills, involved with H+ efflux from acid-secreting cells, basolateral H+ reabsorption for pHi regulation, and in parallel with H+-ATPase for the generation of HCO3− in base-secreting cells.


1996 ◽  
Vol 109 (9) ◽  
pp. 2253-2264 ◽  
Author(s):  
P.R. Odgren ◽  
G. Toukatly ◽  
P.L. Bangs ◽  
R. Gilmore ◽  
E.G. Fey

We have identified and characterized a human protein of the mitochondria which we call mitofilin. Using monoclonal and polyclonal antibodies, we have isolated cDNA clones and characterized mitofilin biochemically. It appears as a 90 and 91 kDa doublet in western blots and is translated from a single 2.7 kb mRNA. Antibodies raised against cellular and bacterially-expressed protein given identical cytoplasmic immunofluorescence and immunoblot results. Mitofilin co-localizes with mitochondria in immunofluorescence experiments and co-purifies with mitochondria. Double label studies show co-localization only with mitochondria and not with Golgi or endoplasmic reticulum. Co-localization with mitochondria is retained when actin or tubulin are de-polymerized, and mitofilin is expressed in all human cell types tested. The cDNA encodes a polypeptide with a central alpha-helical region with predicted coiled coil domains flanked by globular amino and carboxy termini. Unlike coiled coil motor proteins, mitofilin is resistant to detergent extraction. The presence of mitochondrial targeting and stop-transfer sequences, along with the accessibility of mitofilin to limited proteolysis suggests that it resides predominantly in the intermembrane space, consistent with immuno-electron micrographs which show mitofilin mainly at the mitochondrial periphery. The cDNA sequence of mitofilin is identical to that recently reported by Icho et al. (1994; Gene 144, 301–306) for a mRNA preferentially expressed in heart muscle (HMP), consistent with the high levels of mitochondria in cardiac myocytes.


1992 ◽  
Vol 70 (10-11) ◽  
pp. 1030-1038 ◽  
Author(s):  
Qianfa Chen ◽  
Ronald E. Pearlman ◽  
Peter B. Moens

A gene encoding a 65-kilodalton antigen of the rat synaptonemal complex, SC65, has been cloned by screening rat testis λgt11 and λZAPII cDNA expression libraries using polyclonal antibodies against rat synaptonemal complex proteins. The longest open reading frame, initiating at an ATG codon in the cDNA, encodes a protein of 431 amino acids, with a relative molecular mass of 50 000. Immunological analysis locates the SC65 gene product on the synaptonemal complex between the pairing faces of the parallel aligned cores of homologous chromosomes in spermatocytes. Of the rat tissues examined, the SC65 gene is transcribed in testis, brain, and heart at similar levels, and in the liver at a much lower level. The DNA sequence extending about 80 base pairs downstream of the translation termination codon has 93% similarity to the identifier sequence present in the rat genome in 1 × 105 – 1.5 × 105 copies and in cDNA clones of precursors of brain-specific mRNAs. The amino acid sequence encoded by the SC65 gene contains an acidic region in the C-terminal domain of the protein, potential glycosylation sites, and at least one possible phosphorylation site. The protein shows no overall similarity to proteins of known function, nor is there similarity to protein sequences present in GenBank or EMBL data bases.Key words: meiosis, synaptonemal complex, antibody, rat testis cDNA library, molecular cloning.


1986 ◽  
Vol 32 (10) ◽  
pp. 1832-1835 ◽  
Author(s):  
P C Patel ◽  
L Aubin ◽  
J Côte

Abstract We investigated two techniques of immunoblotting--the Western blot and the dot blot--for use in detecting prostatic acid phosphatase (PAP, EC 3.1.3.2). We used polyclonal antisera to human PAP, produced in rabbits by hyperimmunization with purified PAP, and PAP-specific monoclonal antibodies in the immunoenzymatic protocols. We conclude that PAP can be readily detected by Western blots with use of polyclonal antisera, but not with monoclonal antibodies. On the other hand, using a dot blot assay, we could easily detect PAP with both polyclonal and monoclonal antibodies.


Genetics ◽  
1990 ◽  
Vol 126 (4) ◽  
pp. 1033-1044 ◽  
Author(s):  
T Watanabe ◽  
D R Kankel

Abstract Previous genetic studies have shown that wild-type function of the l(1)ogre (lethal (1) optic ganglion reduced) locus is essential for the generation and/or maintenance of the postembryonic neuroblasts including those from which the optic lobe is descended. In the present study molecular isolation and characterization of the l(1)ogre locus was carried out to study the structure and expression of this gene in order to gain information about the nature of l(1)ogre function and its relevance to the development of the central nervous system. About 70 kilobases (kb) of genomic DNA were isolated that spanned the region where l(1)ogre was known to reside. Southern analysis of a l(1)ogre mutation and subsequent P element-mediated DNA transformation mapped the l(1)ogre+ function within a genomic fragment of 12.5 kb. Northern analyses showed that a 2.9-kb message transcribed from this 12.5-kb region represented l(1)ogre. A 2.15-kb portion of a corresponding cDNA clone was sequenced. An open reading frame (ORF) of 1,086 base paris was found, and a protein sequence of 362 amino acids with one highly hydrophobic segment was deduced from conceptual translation of this ORF.


1994 ◽  
Vol 299 (2) ◽  
pp. 545-552 ◽  
Author(s):  
Y Deyashiki ◽  
A Ogasawara ◽  
T Nakayama ◽  
M Nakanishi ◽  
Y Miyabe ◽  
...  

Human liver contains two dihydrodiol dehydrogenases, DD2 and DD4, associated with 3 alpha-hydroxysteroid dehydrogenase activity. We have raised polyclonal antibodies that cross-reacted with the two enzymes and isolated two 1.2 kb cDNA clones (C9 and C11) for the two enzymes from a human liver cDNA library using the antibodies. The clones of C9 and C11 contained coding sequences corresponding to 306 and 321 amino acid residues respectively, but lacked 5′-coding regions around the initiation codon. Sequence analyses of several peptides obtained by enzymic and chemical cleavages of the two purified enzymes verified that the C9 and C11 clones encoded DD2 and DD4 respectively, and further indicated that the sequence of DD2 had at least additional 16 residues upward from the N-terminal sequence deduced from the cDNA. There was 82% amino acid sequence identity between the two enzymes, indicating that the enzymes are genetic isoenzymes. A computer-based comparison of the cDNAs of the isoenzymes with the DNA sequence database revealed that the nucleotide and amino acid sequences of DD2 and DD4 are virtually identical with those of human bile-acid binder and human chlordecone reductase cDNAs respectively.


Parasitology ◽  
2012 ◽  
Vol 139 (8) ◽  
pp. 998-1004 ◽  
Author(s):  
X. CUI ◽  
T. LEI ◽  
D. Y. YANG ◽  
P. HAO ◽  
Q. LIU

SUMMARYImmune mapped protein 1 (IMP1) is a newly discovered protein in Eimeria maxima. It is recognized as a potential vaccine candidate against E. maxima and a highly conserved protein in apicomplexan parasites. Although the Neospora caninum IMP1 (NcIMP1) orthologue of E. maxima IMP1 was predicted in the N. caninum genome, it was still not identified and characterized. In this study, cDNA sequence encoding NcIMP1 was cloned by RT-PCR from RNA isolated from Nc1 tachyzoites. NcIMP1 was encoded by an open reading frame of 1182 bp, which encoded a protein of 393 amino acids with a predicted molecular weight of 42·9 kDa. Sequence analysis showed that there was neither a signal peptide nor a transmembrane region present in the NcIMP1 amino acid sequence. However, several kinds of functional protein motifs, including an N-myristoylation site and a palmitoylation site were predicted. Recombinant NcIMP1 (rNcIMP1) was expressed in Escherichia coli and then purified rNcIMP1 was used to prepare specific antisera in mice. Mouse polyclonal antibodies raised against the rNcIMP1 recognized an approximate 43 kDa native IMP1 protein. Immunofluorescence analysis showed that NcIMP1 was localized on the membrane of N. caninum tachyzoites. The N-myristoylation site and the palmitoylation site were found to contribute to the localization of NcIMP1. Furthermore, the rNcIMP1-specific antibodies could inhibit cell invasion by N. caninum tachyzoites in vitro. All the results indicate that NcIMP1 is likely to be a membrane protein of N. caninum and may be involved in parasite invasion.


1992 ◽  
Vol 12 (12) ◽  
pp. 5673-5682 ◽  
Author(s):  
A D Bergemann ◽  
Z W Ma ◽  
E M Johnson

The human Pur factor binds strongly to a sequence element repeated within zones of initiation of DNA replication in several eukaryotic cells. The protein binds preferentially to the purine-rich single strand of this element, PUR. We report here the cloning and sequencing of a cDNA encoding a protein with strong affinity for the PUR element. Analysis with a series of mutated oligonucleotides defines a minimal single-stranded DNA Pur-binding element. The expressed Pur open reading frame encodes a protein of 322 amino acids. This protein, Pur alpha, contains three repeats of a consensus motif of 23 amino acids and two repeats of a second consensus motif of 26 amino acids. Near its carboxy terminus, the protein possesses an amphipathic alpha-helix and a glutamine-rich domain. The repeat region of Pur cDNA is homologous to multiple mRNA species in each of several human cell lines and tissues. The HeLa cDNA library also includes a clone encoding a related gene, Pur beta, containing a version of the 23-amino-acid consensus motif similar, but not identical, to those in Pur alpha. Results indicate a novel type of modular protein with capacity to bind repeated elements in single-stranded DNA.


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