Search results for "Base Sequence"
showing 10 items of 1146 documents
A novel member of an ancient superfamily: sponge (Geodia cydonium, Porifera) putative protein that features scavenger receptor cysteine-rich repeats
1997
Proteins featuring scavenger receptor cysteine-rich (SRCR) domains are prominent receptors known from vertebrates and from one phylum of invertebrates, the echinoderms. In the present study we report the first putative SRCR protein from the marine sponge Geodia cydonium (Porifera), a member of the lowest phylum of contemporary Metazoans. Two forms of SRCR molecules were characterized, which apparently represent alternative splicing of the same transcript. The long putative SRCR protein, of 1536 aa, features twelve SRCR repeats, a C-terminal transmembrane domain and a cytoplasmic tail. The sequence of the short form is identical with the long form except that it lacks a coding region near th…
Human fetal adrenal hydroxysteroid sulphotransferase: cDNA cloning, stable expression in V79 cells and functional characterisation of the expressed e…
1995
Dehydroepiandrosterone sulphate (DHEAS) is a major adrenal secretory product, particularly in the fetus where it serves as a substrate for oestrogen biosynthesis by the placenta. The enzyme in the adrenal responsible for synthesising DHEAS, hydroxysteroid sulphotransferase (HST), is therefore essential for human development. We have isolated a full-length cDNA clone, encoding human fetal adrenal HST, and constructed a stable cell line expressing it by transfection into V79 Chinese hamster lung fibroblast cells. This cDNA was essentially identical to that isolated from adult human liver, where the role of HST is less well understood. This recombinant cell line allowed determination of the su…
A novel tunicate (Botryllus schlosseri) putative C-type lectin features an immunoglobulin domain.
1997
We have cloned a putative C-type lectin of Botryllus schlosseri [Ascidiacea], whose deduced protein of 333 amino acids features three building blocks: (i) a Greek-key motif signature at the amino-terminus, (ii) a C-type lectin domain signature, and (iii) an immunoglobulin (Ig) domain at the carboxyl terminus. This C-type lectin was termed BSCLT. Similarity searches revealed that the Ig domain in BSCLT, which is evidently not polymorphic, is best classified as an Intermediate-type Ig domain. Rabbit antibodies, raised against recombinant BSCLT, cross-reacted in a Western blot with a 38-kD polypeptide in tunicate crude extract. Presumably, this bimodal tunicate protein is the first description…
Increased Expression of Integrin and Receptor Tyrosine Kinase Genes During Autograft Fusion in the SpongeGeodia cydonium
1999
Recently cDNAs coding for cell surface molecules have been isolated from sponges. The molecules for alpha-integrin, galectin, and receptor tyrosine kinase (RTK), obtained from the marine sponge, Geodia cydonium, have been described earlier. In the present study also the cDNA for one putative beta-integrin has been identified from G. cydonium. The deduced aa sequence comprises the characteristic signatures, found in other metazoan beta-integrin molecules; the estimated size is 95,215 Da. To obtain first insights into the molecular events which proceed during autograft fusion, the expressions of these genes were determined on transcriptional and translational level. The cDNAs as well as antib…
Evolutionary relationships of the metazoan βγ–crystallins, including that from the marine spongeGeodia cydonium
1997
beta gamma-crystallins are one major component of vertebrate lenses. Here the isolation and characterization of a cDNA, coding for the first beta gamma-crystallin molecule from an invertebrate species, the marine sponge Geodia cydonium, is described. The size of the transcript as determined by Northern blotting was 0.7 kb in length. The deduced amino acid sequence consists of 163 aa residues and comprises four repeated motifs which compose the two domains of the beta gamma-crystallin. Motif 3 contains the characteristic beta gamma-crystallin 'Greek key' motif signature, while in each of the three other repeats, one aa residue is replaced by an aa with the same physico-chemical property. The…
Evolutionary relationships of Metazoa within the eukaryotes based on molecular data from Porifera
1999
Recent molecular data provide strong support for the view that all metazoan phyla, including Porifera, are of monophyletic origin. The relationship of Metazoa, including the Porifera, to Plantae, Fungi and unicellular eukaryotes has only rarely been studied by using cDNAs coding for proteins. Sequence data from rDNA suggested a relationship of Porifera to unicellular eukaryotes (choanoflagellates). However, ultrastructural studies of choanocytes did not support these findings. In the present study, we compared amino acid sequences that are found in a variety of metazoans (including sponges) with those of Plantae, Fungi and unicellular eukaryotes, to obtain an answer to this question. We use…
Experimental indication in favor of the introns-late theory: the receptor tyrosine kinase gene from the sponge Geodia cydonium.
1997
Abstract We have analyzed the gene that encodes receptor tyrosine kinase (RTK) from the marine sponge Geodia cydonium, which belongs to the most ancient and simple metazoan groups, the Porifera. RTKs are enzymes found only in metazoa. The sponge gene contains two introns in the extracellular part of the protein. However, the rest of the protein (transmembrane and intracellular part), including the tyrosine kinase (TK)-domain, is encoded by a single exon. In contrast, all TK genes, so far known only from higher animals (vertebrates), contain several introns especially in the TK-domain. The TK-domain of G. cydonium shows similarity with numerous members of receptor as well as nonreceptor TKs.…
Molecular cloning of a tyrosine kinase gene from the marine spongeGeodia cydonium: a new member belonging to the receptor tyrosine kinase class II fa…
1994
We have isolated and characterized a cDNA from the marine sponge Geodia cydonium coding for a new member of the tyrosine protein kinase (TK) family. The cDNA encodes a protein of M(r) = 68,710, termed GCTK, which is homologous to class II receptor tyrosine kinases (RTKs). GCTK contains conserved amino acids (aa) characteristic of all protein kinases, and the sequences DLATRN and PIRWMATE which are highly specific for TKs. Furthermore, the sequence N-L-Y-x(3)-Y-Y-R is highly homologous to the sequence D-[LIV]-Y-x(3)-Y-Y-R found only in class II RTKs. The sponge TK, when compared with mammalian class II RTKs, shows maximum 31% homology in the TK domain indicating that this the oldest member o…
A hemocyanin from the Onychophora and the emergence of respiratory proteins
2002
The velvet worms (Onychophora) are considered living fossils and are closely related to the Euarthropoda. Onychophora possess a tracheal system for respiratory function, but oxygen-transport proteins have been considered unnecessary. Here, we show that the hemolymph of the Epiperipatus sp. (Onychophora: Peripatidae) contains an arthropod-type hemocyanin, demonstrating that such protein exists outside the Euarthropoda. Thus, the evolution of oxygen carriers preceded the divergence of the Onychophora and Euarthropoda and was most likely linked to the evolution of an efficient circulatory system in a low-oxygen environment. The cDNA of the Epiperipatus hemocyanin subunit comprises 2,287 bp an…
Expression of a plant serine O-acetyltransferase inSaccharomyces cerevisiae confers osmotic tolerance and creates an alternative pathway for cysteine…
2004
Screening of a sugar beet (Beta vulgaris cv. Dita) cDNA library for clones able to confer osmotic tolerance to the osmosensitive gpd1 mutant of Saccharomyces cerevisiae identified a novel serine O-acetyltransferase (BvSAT; EC 2.3.1.30). This enzyme is involved in cysteine biosynthesis in plants and bacteria, producing O-acetylserine, which is converted into cysteine in a reaction catalysed by O-acetylserine sulphydrylase (EC 4.2.99.8). This pathway is not conserved in yeast, where cysteine is synthesized in a four-step pathway starting with homoserine and having O-acetylhomoserine, homocysteine and cystathionine as intermediates. Expression of BvSAT in yeast takes advantage of the activity …