Expression of a novel cadherin (EP-cadherin) in unfertilized eggs and early Xenopus embryos

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 315-325 ◽  
Author(s):  
D. Ginsberg ◽  
D. DeSimone ◽  
B. Geiger

Two distinct cadherin cDNA clones of Xenopus laevis were isolated from a stage 17 embryo cDNA library. Analysis of the complete deduced amino acid sequences indicated that one of these molecules is closely homologous to chicken and mouse N-cadherin, while the other displays comparable homology to both E- and P-cadherins and was thus denoted EP-cadherin. This molecule has an apparent relative molecular mass of 125 × 10(3) (compared to approx. 138 × 10(3) or approx. 140 × 10(3) of E-cadherin and N-cadherins, respectively). Northern and Western blot analyses indicated that N-cadherin is first expressed at the neurula stage while EP-cadherin is the only cadherin detected in unfertilized eggs and cleavage stage embryos. Immunolabeling of Xenopus eggs with antibodies prepared against a fusion protein, containing a segment of EP-cadherin, indicated that the protein is highly enriched at the periphery of the animal hemisphere. EP-cadherin was also found in A6 epithelial cells derived from Xenopus kidneys, and was apparently localized in the intercellular adherens junctions.

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.


1991 ◽  
Vol 98 (1) ◽  
pp. 27-36
Author(s):  
S.J. Chapin ◽  
J.C. Bulinski

A polyclonal antiserum raised against a HeLa cell microtubule-associated protein of Mr 210,000 (210 kD MAP or MAP4), an abundant non-neuronal MAP, was used to isolate cDNA clones encoding MAP4 from a human fetal brain lambda gt11 cDNA expression library. The largest of these clones, pMAP4.245, contains an insert of 4.1 kb and encodes a 245 kD beta-galactosidase fusion protein. Evidence that pMAP4.245 encodes MAP4 sequences includes immunoabsorption of MAP4 antibodies with the pMAP4.245 fusion protein, as well as identity of protein sequences obtained from HeLa 210 kD MAP4 with amino acid sequences encoded by pMAP4.245. The MAP4.245 cDNA hybridizes to several large (approximately 6–9 kb) transcripts on Northern blots of HeLa cell RNA. DNA sequencing of overlapping MAP4 cDNA clones revealed a long open reading frame containing a C-terminal region with three imperfect 18-amino acid repeats; this region is homologous to a motif present in the microtubule (MT)-binding domain of two prominent neuronal MAPs, MAP2 and tau. The pMAP4.245 sequence also encoded a series of unrelated repeats, located in the MAP's projection domain, N-terminal to the MT-binding domain. MAP4.245 fusion proteins bound to MTs in vitro, while fusion proteins that contained only the projection domain repeats failed to bind specifically to MTs. Thus, the major human non-neuronal MAP resembles two neuronal MAPs in its MT-binding domain, while most of the molecule has sequences, and presumably functions, distinct from those of the neuronal MAPs.


1992 ◽  
Vol 284 (3) ◽  
pp. 795-802 ◽  
Author(s):  
J Lu ◽  
A C Willis ◽  
K B M Reid

Human pulmonary surfactant protein D (SP-D) was identified in lung lavage by its similarity to rat SP-D in both its molecular mass and its Ca(2+)-dependent-binding affinity for maltose [Persson, Chang & Crouch (1990) J. Biol. Chem. 265, 5755-5760]. For structural studies, human SP-D was isolated from amniotic fluid by affinity chromatography on maltose-Sepharose followed by f.p.l.c. on Superose 6, which showed it to have a molecular mass of approx. 620 kDa in non-dissociating conditions. On SDS/PAGE the human SP-D behaved as a single band of 150 kDa or 43 kDa in non-reducing or reducing conditions respectively. The presence of a high concentration of glycine (22%), hydroxyproline and hydroxylysine in the amino acid composition of human SP-D indicated that it contained collagen-like structure. Collagenase digestion yielded a 20 kDa collagenase-resistant globular fragment which retained affinity for maltose. Use of maltosyl-BSA as a neoglycoprotein ligand in a solid-phase binding assay showed that human SP-D has a similar carbohydrate-binding specificity to rat SP-D, but a clearly distinct specificity from that of other lectins, such as conglutinin, for a range of simple saccharides. Amino acid sequence analysis established the presence of collagen-like Gly-Xaa-Yaa triplets in human SP-D and also provided sequence data from the globular region of the molecule which was used in the synthesis of oligonucleotide probes. Screening of a human lung cDNA library with the oligonucleotide probes, and also with rabbit anti-(human SP-D), allowed the isolation of two cDNA clones which overlap to give the full coding sequence of human SP-D. The derived amino acid sequence indicates that the mature human SP-D polypeptide chain is 355 residues long, having a short non-collagen-like N-terminal section of 25 residues, followed by a collagen-like region of 177 residues and a C-terminal C-type lectin domain of 153 residues. Comparison of the human SP-D and bovine serum conglutinin amino acid sequences indicated that they showed 66% identity despite their marked differences in carbohydrate specificity.


1985 ◽  
Vol 101 (3) ◽  
pp. 1044-1051 ◽  
Author(s):  
W Y Kao ◽  
S T Case

Chironomus salivary glands contain a family of high Mr (approximately 1,000 X 10(3)) secretion polypeptides thought to consist of three components: sp-Ia, sp-Ib, and sp-Ic. The use of a new extraction protocol revealed a novel high Mr component, sp-Id. Results of a survey of individual salivary glands indicated that sp-Id was widespread in more than a dozen strains of C. tentans and C. pallidivittatus. Sp-Id was phosphorylated at Ser residues, and a comparison of cyanogen bromide and tryptic peptide maps of 32P-labeled polypeptides suggested that sp-Ia, sp-Ib, and sp-Id are comprised of similar but nonidentical tandemly repeated amino acid sequences. We concluded that sp-Id is encoded by an mRNA whose size and nucleotide sequence organization are similar to Balbiani ring (BR) mRNAs that code for the other sp-I components. Furthermore, parallel repression of sp-Ib and sp-Id synthesis by galactose led us to hypothesize that both of their genes exist within Balbiani ring 2.


1993 ◽  
Vol 291 (3) ◽  
pp. 787-792 ◽  
Author(s):  
R Z Zhang ◽  
T C Pan ◽  
R Timpl ◽  
M L Chu

cDNA clones encoding the alpha 1, alpha 2 and alpha 3 chains of mouse collagen VI have been isolated by screening cDNA libraries with the corresponding human probes. The composite cDNAs for the alpha 1, alpha 2, and alpha 3 chains are 2.5, 1.6 and 2.9 kb in size respectively. The alpha 1 and alpha 2 cDNAs encode the C-terminal portions of the chains as well as the entire 3′-untranslated regions, while the alpha 3 cDNAs encode a central segment of 959 amino acids flanking the triple-helical domain. The deduced amino acid sequences share 86-88% identity with the human counterparts and 67-73% identity with the chicken equivalents. Alignment of the deduced amino acid sequences of mouse, human and chicken collagens reveal that the key features of the protein, including the cysteine residues, imperfections in the Gly-Xaa-Xaa regions, Arg-Gly-Asp sequences and potential N-glycosylation sites, are mostly conserved.


1989 ◽  
Vol 3 (2) ◽  
pp. 105-112 ◽  
Author(s):  
T. S. Grewal ◽  
P. J. Lowry ◽  
D. Savva

ABSTRACT A large portion of the human pro-opiomelanocortin (POMC) peptide corresponding to amino acid residues 59–241 has been cloned and expressed in Escherichia coli. A 1·0 kb DNA fragment encoding this peptide was cloned into the expression vectors pUC8 and pUR291. Plasmid pJMBG51 (a pUC8 recombinant) was found to direct the expression of a 24 kDa peptide. The recombinant pUR291 (pJMBG52) was shown to produce a β-galactosidase fusion protein of 140 kDa. Western blot analysis showed that both the 24 kDa and 140 kDa peptides are recognized by antibodies raised against POMC-derived peptides. The β-galactosidase fusion protein has been partially purified from crude E. coli cell lysates using affinity chromatography on p-aminobenzyl-1-thio-β-d-galactopyranoside agarose.


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.


1992 ◽  
Vol 118 (6) ◽  
pp. 1465-1475 ◽  
Author(s):  
J A Marrs ◽  
G B Bouck

60% of the peripheral membrane skeleton of Euglena gracilis consists of equimolar amounts of two proteins (articulins) with M(r)s in SDS gels of 80 and 86 kD. To understand eventually how these proteins assemble and function in maintaining cell form and membrane integrity we have undertaken a molecular characterization of articulins. A lambda gt11 expression library constructed from Euglena gracilis mRNAs was screened with antibodies against both articulins. Two sets of cDNAs were recovered, and evidence from three independent assays confirmed that both sets encoded articulins: (a) Anti-articulin antibodies recognized a high molecular weight beta-galactosidase (beta-gal) fusion protein expressed in bacteria infected with lambda gt11 cDNA clones. (b) Antibodies generated against the bacterially expressed beta-gal fusion protein identified one or the other articulin in Western blots of Euglena proteins. These antibodies also localized to the membrane skeletal region in thin sections of Euglena. (c) Peptide maps of the beta-gal fusion protein were similar to peptide maps of Euglena articulins. From the nucleotide sequence of the two sets of cDNAs an open reading frame for each articulin was deduced. In addition to 37% amino acid identity and overall structural similarity, both articulins exhibited a long core domain consisting of over 30 12-amino acid repeats with the consensus VPVPV--V--. Homology plots comparing the same or different articulins revealed larger, less regular repeats in the core domain that coincided with predicted turns in extended beta-sheets. Outside the core domain a short hydrophobic region containing four seven-amino acid repeats (consensus: APVTYGA) was identified near the carboxy terminus of the 80-kD articulin, but near the amino terminus of the 86-kD articulin. No extensive sequence similarities were found between articulins and other protein sequences in various databanks. We conclude that the two articulins are related members of a new class of membrane cytoskeletal proteins.


Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 279-298
Author(s):  
H. Herrmann ◽  
B. Fouquet ◽  
W.W. Franke

To provide a basis for studies of the expression of genes encoding the diverse kinds of intermediate-filament (IF) proteins during embryogenesis of Xenopus laevis we have isolated and characterized IF protein cDNA clones. Here we report the identification of two types of Xenopus vimentin, Vim1 and Vim4, with their complete amino acid sequences as deduced from the cloned cDNAs, both of which are expressed during early embryogenesis. In addition, we have obtained two further vimentin cDNAs (Vim2 and 3) which are sequence variants of closely related Vim1. The high evolutionary conservation of the amino acid sequences (Vim1: 458 residues; Mr approximately 52,800; Vim4: 463 residues; Mr approximately 53,500) to avian and mammalian vimentin and, to a lesser degree, to desmin from the same and higher vertebrate species, is emphasized, including conserved oligopeptide motifs in their head domains. Using these cDNAs in RNA blot and ribonuclease protection assays of various embryonic stages, we observed a dramatic increase of vimentin RNA at stage 14, in agreement with immunocytochemical results obtained with antibody VIM-3B4. The significance of very weak mRNA signals detected in earlier stages is discussed in relation to negative immunocytochemical results obtained in these stages. The first appearance of vimentin has been localized to a distinct mesenchymal cell layer underlying the neural plate or tube, respectively. The results are discussed in relation to programs of de novo synthesis of other cytoskeletal proteins in amphibian and mammalian development.


1996 ◽  
Vol 49 (12) ◽  
pp. 1325 ◽  
Author(s):  
AM Bradford ◽  
JH Bowie ◽  
MJ Tyler ◽  
JC Wallace

The dorsal glandular extract of the toadlet Uperoleia mjobergii contains more than 20 peptides. We report the amino acid sequences of the seven major peptides: these were determined by a combination of mass spectrometry and automated Edman sequencing. Three of these peptides have 19 amino acid residues and belong to the uperin 2 group of peptides [e.g. uperin 2.6, Gly Ile Leu Asp Ile Ala Lys Lys Leu Val Gly Gly Ile Arg Asn Val Leu Gly Ile (OH)], while the other four have 17 residues and are classified as uperins 3 [e.g. Uperin 3.4, Gly Val Gly Asp Leu Ile Arg Lys Ala Val Ala Ala Ile Lys Asn Ile Val (NH2)]. Several of these cationic peptides have been synthesized in order for bioassays to be carried out: they show significant antibiotic activity against a range of Gram-positive microorganisms. A major skin peptide from the related species Uperoleia inundata is a powerful neuropeptide named uperin 1.1 ([Ala2] uperolein ): no corresponding neuropeptide is detected in the skin glands of Uperoleia mjobergii.


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