XB-ART-24384J Biol Chem 1991 Nov 05;26631:21306-9.
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Two different precursors for secretory polypeptides from the stomach of Xenopus laevis have been characterized by cDNA cloning. Both mature polypeptides are potential candidates for gastrointestinal growth factors. One, xP1, is the X. laevis homologue of the pS2 gene product consisting only of a single P-domain, whereas the second, xP4, is a novel polypeptide formed by four P-domains arranged in tandem. Northern analysis detected both transcripts in the stomach but not in the skin or the brain. In situ hybridizations localized the expression of both precursors in surface mucous cells of the gastric mucosa. With an antibody generated against the deduced C-terminal end of xP4, the mature polypeptide was investigated by Western analysis revealing N-glycosylation of xP4.
PubMed ID: 1939167
Article link: J Biol Chem
Species referenced: Xenopus laevis
Genes referenced: ide tbx2 tff3.1 tff3.8
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|FIG. 1. Nucleotide sequence and translation of the xPl transcript as deduced from eDNA clones pXSP-5' -3.3 (positions 1-258) and pXSP-3' -4.1 (positions 183-483). 'fhe potential cleavage site for signal peptidase is indicated by an arrow. 'fhe conserved tryptophan residue in the P-domain is encircled, and the polyadenylation signal and a restriction site are underlined. Also marked are the positions of the synthetic oligonucleotides.|
|FIG. 2. Nucleotide sequence and t ranslation of the xP4 transcript as deduced from eDNA clones pXSP- 5'-1.27 (positions 1- 730} and pXSP-3'-2.1 (pos itions 304-854). 'fhe potential cleavage site for signal 1 peptidase is indicated by an arrow. 'fhe , conserved tryptophan residue in each p. j domain is encircled, the polyadenylation . signal, restriction sites, and the potential ~ N-glycosylation site are underlined. Also : marked are the positions of the synthetic ; oligonucleotides. 'fhe sequence selected ' for the synthetic peptide (XGP-1) is in · : dicated by a dotted line.|
|FIG. 3. Northern analysis. Hybridization of 20 ;.tg of total RNA from X. laeu/$ skin (lanes a and d), stomach (lanes b and e), and brain (lanes c and f) with the radioactively labeled inserts of eDNA clone pXSP-3'·4.1 (encoding xPL; lanes a-c) or pXSP-3'-2.5 (encoding xP4, similar pXSP-3'-2.1; lanes d-f). As a size marker, a RNA ladder was used (purchased from Bethesda Research Laboratories).|
|FIG. 4. In situ hybridizations to sections through fundic regions of X. laevis stomach. A, 8, C, hybridi7.a· tion with ' H-labeled single-stranded cRNAs representing xP1 (from eDNA clone pXSP-3' ·4.1}; exposure time, 14 days. D, E, F, hybridization with 32PIabeled single-stranded cRNAs repre· senting xP4 (from eDNA clone pXSP· 5' -1.26, similar pXSP-5' -1.27); exposure time, 5 days. Positive signals (dark/ieki illumination) were obtained with the an· tisense probes (A, D), but not with the sense probes (C, F). 8, E, corresponding phase contrast pictures to A and D. Scale|
|Ftc. 5. SDS-polyacrylamide gel e lectrophoresis (15%) and s ubsequent Wester n a na lysis. Lanes a, c, d, and e, X . laeuis stomach extract. Lane b, X. laeuis stomach extract after digestion with glycopeptidase-F. In lanes a- d, staining with antiserum XGP-1 is shown either directly (lanes a and b) or after preadsorption with peptide XGP·l (lane c) or peptide XGP-2 (lane d), whereas lane e represents reaction with preimmune serum.|
|F1G. 6. Comparison of a ll P-domains from X. laevis ide ntified so far (xPl; xP4; FlM-A.l, Hoffmann, 1988; p75 k , Gmnchl et al., 1990) and human p82 (Jakolew et al., 1984). Invariant amino acid residues are enclosed in boxes. 'fhe 6 characteristic cysteine residues are numbered. Bars mark deletions to maximize homo I· ogy.|