Linked Life Data

2330002

Source:http://linkedlifedata.com/resource/pubmed/id/2330002

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-5-31
pubmed:databankReference
pubmed:abstractText
By means of a cloning strategy employing the polymerase chain reaction, we have isolated and characterized cDNAs for Xenopus laevis insulin-like growth factor I (IGF-I). These cDNAs encode a primary IGF-I translation product of 153 residues that demonstrates considerable amino acid sequence similarity with IGF-IA peptides from other species. Fifty-seven of 70 residues of the mature protein are identical among human, rat, chicken, and Xenopus IGF-I, while less amino acid conservation is found at the COOH-terminus (25/35 identities) or at the NH2-terminus (24/48 identities) of the precursor protein. Despite the lower degree of structural similarity at the NH2-terminus, in vitro studies of IGF-I biosynthesis and proteolytic processing support a conserved function for the atypically long 48 residue NH2-terminal signal sequence in directing the nascent IGF-I peptide through the secretory pathway. The 5'-untranslated region of Xenopus IGF-I mRNA matches the human, rat, and chicken sequences in greater than 90% of 279 nucleotides. IGF-I mRNAs from all four species encode a conserved upstream open reading frame of 14 amino acids starting 240-250 nucleotides 5' to the translation start site, suggesting a possible role for this region in modulating IGF-I gene expression. The X. laevis IGF-I gene is transcribed and processed into three mRNAs of 1.6, 2.1, and 3.0 kilobases in liver, and IGF-I mRNAs can be detected in liver, lung, heart, kidney, and peritoneal fat of adult animals. These studies demonstrate that both the IGF-I protein precursor and potential regulatory regions of IGF-I mRNA have been conserved during vertebrate evolution, and indicate that like several other polypeptide growth factors, IGF-I may be of fundamental importance in regulating specific aspects of growth and development in all vertebrates.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0888-8809
pubmed:author
pubmed:issnType
Print
pubmed:volume
4
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
217-26
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Evolution of insulin-like growth factor I (IGF-I): structure and expression of an IGF-I precursor from Xenopus laevis.
pubmed:affiliation
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.