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Chinese Science Bulletin

, Volume 51, Issue 22, pp 2731–2736 | Cite as

Alternative splicing and expression of the insulin-like growth factor (IGF-1) gene in osteoblasts under mechanical stretch

  • Xian Chengyu 
  • Wang Yuanliang Email author
  • Zhang Bingbing 
  • Tang Liling 
  • Pan Jun 
  • Luo Yanfeng 
  • Jiang Peng 
  • Li Dajun 
Articles

Abstract

Insulin-like growth factor 1 (IGF-1) promotes osteoblasts differentiation and bone formation, and its expression is induced by mechanical stretch, thus IGF-1 has been considered an effector molecule that links mechanical stimulation and local tissue responses. In this study, a mechanical stretching device was designed to apply physiological level static or cyclic stretching stimulation to osteoblasts. Different isoforms of IGF-1 mRNA were amplified by RT-PCR from the cells using respective primers and these amplified products were sequenced. An isoform of IGF-1 splicing product was found to be selectively produced by osteoblasts under stretching stimulation. This IGF-1 isoform had identical sequence with the mechano growth factor (MGF) which was originally identified in muscle cells. Regulations of the expression of the liver-type IGF (L.IGF-1) and MGF in osteoblasts under stretch stimulation were further studied using semi-quantitative RT-PCR. Stretch stimulation was found to promot the expression of IGF-1 (L.IGF-1 and MGF), and for both isoforms expression was more effectively stimulated by cyclic stretch than static stretch. MGF was detected only in osteoblasts subjected to mechanical stretch, suggesting MGF was a stretch sensitive growth factor. Expression of MGF peaked earlier than that of L.IGF-1, which was similar to their regulation in muscle and suggested similar roles of MGF and L.IGF-1 in bone as in muscle cells. The functions of MGF and L.IGF-1 in osteoblasts shall be established by further experimental studies.

Keywords

insulin-like growth factor-1 (IGF-1) mechano growth factor (MGF) alternative splice osteoblasts stretching 

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Copyright information

© Science in China Press 2006

Authors and Affiliations

  • Xian Chengyu 
    • 1
  • Wang Yuanliang 
    • 1
    Email author
  • Zhang Bingbing 
    • 1
  • Tang Liling 
    • 1
  • Pan Jun 
    • 1
  • Luo Yanfeng 
    • 1
  • Jiang Peng 
    • 1
  • Li Dajun 
    • 1
  1. 1.Bioengineering College, Research Center of Bioinspired Materials Science and Engineering, Key Laboratory for Biomechanics & Tissue Engineering Under The State Ministry of EducationChongqing UniversityChongqingChina

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