Differential gene expression of vascular endothelial growth factor isoforms and their receptors in the development of the rat masseter muscle.
The capillary network in the masseter muscle develops dramatically with the differentiation of muscle fibres after birth, especially around weaning. Here, developmental changes in mRNA expression for four splicing variants of vascular endothelial growth factor (VEGF) and for two distinct VEGF receptors (Fms-like tyrosine kinase (Flt-1) and kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/Flk-1)) were studied in rat masseter. The relative abundance of VEGF (120) mRNA was the highest, representing 35% of total VEGF mRNA on day 7 after birth and gradually decreased with age to become approximately 5% on day 37. In contrast, VEGF (188) mRNA was very low in the newborn rat, but increased sharply before weaning and reached 40-50% of the total on day 50. Neither VEGF (144) nor VEGF(164) mRNA showed any significant change in abundance after birth. The expression of KDR/Flk-1 mRNA was transiently high in the early postnatal stage and gradually decreased with age, Flt-1 mRNA was stably expressed at a constant level after birth. These findings suggest that different combinations of VEGF isoforms and their receptors regulate angiogenesis in the development of the masseter muscle.
Department of Oral Physiology, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu, Hokkaido 061-0293, Japan. hisayosh@hoku-iryo-u.ac.jp
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Ishii
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Oota
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Arakawa
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Takuma
D017398:Alternative Splicing; D000818:Animals; D016228:Endothelial Growth Factors / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D008222:Lymphokines / Q000096:biosynthesis* / Q000235:genetics; D008406:Masseter Muscle / Q000098:blood supply* / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000235:genetics*; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D040262:Receptors, Vascular Endothelial Growth Factor / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000096:biosynthesis; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D020033:Protein Isoforms; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D040262:Receptors, Vascular Endothelial Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2