| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Northwest Fisheries Science Center, NOAA Fisheries, 2725 Montlake Boulevard East, Seattle, Washington 98112, USA
2 School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA
(Requests for offprints should be addressed to M Shimizu; Email: munetaka.shimizu{at}noaa.gov)
Western ligand blotting of salmon serum typically reveals three insulin-like growth factor (IGF) binding proteins (IGFBPs) at 22, 28 and 41 kDa. Physiologic regulation of the 22 kDa IGFBP is similar to that of mammalian IGFBP-1; it is increased in catabolic states such as fasting and stress. On the other hand, its molecular mass on Western ligand blotting is closest to mammalian IGFBP-4. The conflict between physiology and molecular mass makes it difficult to determine the identity of the 22 kDa IGFBP. This study therefore aimed to identify the 22 kDa IGFBP from protein and cDNA sequences. The 22 kDa IGFBP was purified from chinook salmon serum by a combination of IGF-affinity chromatography and reverse-phase chromatography. The N-terminal aminoacid sequence of the purified protein was used to design degenerate primers. Degenerate PCR with liver template amplified a partial IGFBP cDNA, and full-length cDNA was obtained by 5'- and 3'-rapid amplification of cDNA ends (RACE). The 1915-bp cDNA clone encodes a 23.8 kDa IGFBP, and its N-terminal amino-acid sequence matched that of purified 22 kDa IGFBP. Sequence comparison with six human IGFBPs revealed that it is most similar to IGFBP-1 (40% identity and 55% similarity). These findings indicate that salmon 22 kDa IGFBP is IGFBP-1. Salmon IGFBP-1 mRNA is predominantly expressed in the liver, and its expression levels appear to reflect circulating levels. The 3'-untranslated region of salmon IGFBP-1 mRNA contains four repeats of the nucleotide sequence ATTTA, which is involved in selective mRNA degradation. In contrast, amino-acid sequence analysis revealed that salmon IGFBP-1 does not have an Arg-Gly-Asp (RGD) integrin recognition sequence nor a Pro, Glu, Ser and Thr (PEST)-rich domain (a segment involved in rapid turnover of protein), both of which are characteristic of mammalian IGFBP-1. These findings suggest that association with the cell surface and turnover rate may differ between salmon and mammalian IGFBP-1.
This article has been cited by other articles:
|
|
 |
|
  F. W. Goetz, M. L. Rise, M. Rise, G. W. Goetz, F. Binkowski, and B. S. Shepherd Stimulation of growth and changes in the hepatic transcriptome by 17{beta}-estradiol in the yellow perch (Perca flavescens) Physiol Genomics, August 7, 2009; 38(3): 261 - 280. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Shimizu, K. A. Cooper, W. W. Dickhoff, and B. R. Beckman Postprandial changes in plasma growth hormone, insulin, insulin-like growth factor (IGF)-I, and IGF-binding proteins in coho salmon fasted for varying periods Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2009; 297(2): R352 - R361. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Li, Y. Li, L. Lu, X. Wang, Q. Gong, and C. Duan Structural, gene expression, and functional analysis of the fugu (Takifugu rubripes) insulin-like growth factor binding protein-4 gene Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2009; 296(3): R558 - R566. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A L Pierce, M Shimizu, L Felli, P Swanson, and W W Dickhoff Metabolic hormones regulate insulin-like growth factor binding protein-1 mRNA levels in primary cultured salmon hepatocytes; lack of inhibition by insulin. J. Endocrinol., November 1, 2006; 191(2): 379 - 386. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. B. Kamangar, J.-C. Gabillard, and J. Bobe Insulin-Like Growth Factor-Binding Protein (IGFBP)-1, -2, -3, -4, -5, and -6 and IGFBP-Related Protein 1 during Rainbow Trout Postvitellogenesis and Oocyte Maturation: Molecular Characterization, Expression Profiles, and Hormonal Regulation Endocrinology, May 1, 2006; 147(5): 2399 - 2410. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
