title: Purification, cDNA structure and biological significance of a single insulin-like growth factor-binding domain protein (SIBD-1) identified in the hemocytes of the spider Cupiennius salei.
abstract: Cupiennius salei single insulin-like growth factor-binding domain protein (SIBD-1), which exhibits an IGFBP N-terminal domain-like profile, was identified in the hemocytes of the spider C. salei. SIBD-1 was purified by RP-HPLC and the sequence determined by a combination of Edman degradation and 5'-3'- RACE PCR. The peptide (8676.08 Da) is composed of 78 amino acids, contains six intrachain disulphide bridges and carries a modified Thr residue at position 2. SIBD-1 mRNA expression was detected by quantitative real-time PCR mainly in hemocytes, but also in the subesophageal nerve mass and muscle. After infection, the SIBD-1 content in the hemocytes decreases and, simultaneously, the temporal SIBD-1 expression seems to be down-regulated. Two further peptides, SIBD-2 and IGFBP-rP1, also exhibiting IGFBP N-terminal domain variants with unknown functions, were identified on cDNA level in spider hemocytes and venom glands. We conclude that SIBD-1 may play an important role in the immune system of spiders.
authors: Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland. lucia.kuhn@iee.unibe.ch
authors: Lucia
authors: L
authors: Kuhn-Nentwig
authors: Carlo R
authors: CR
authors: Largiadèr
authors: Kathrin
authors: K
authors: Streitberger
authors: Sathyan
authors: S
authors: Chandru
authors: Tommy
authors: T
authors: Baumann
authors: Urs
authors: U
authors: Kämpfer
authors: Johann
authors: J
authors: Schaller
authors: Stefan
authors: S
authors: Schürch
authors: Wolfgang
authors: W
authors: Nentwig
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D006434:Hemocytes / Q000737:chemistry* / Q000378:metabolism; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013112:Spiders / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D060829:Arthropod Proteins; D018969:Insulin-Like Growth Factor Binding Proteins