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Expression of genes of type I and type II collagen in the formation and development of the blastema of regenerating newt limb
Author(s) -
Asahina Kinji,
Obara Masanobu,
Yoshizato Katsutoshi
Publication year - 1999
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/(sici)1097-0177(199909)216:1<59::aid-dvdy8>3.0.co;2-b
Subject(s) - blastema , biology , mesenchymal stem cell , basement membrane , epidermis (zoology) , regeneration (biology) , microbiology and biotechnology , in situ hybridization , type i collagen , type iv collagen , extracellular matrix , anatomy , gene expression , collagen, type i, alpha 1 , gene , endocrinology , genetics , laminin
We cloned cDNAs of α1(I) and α1(II) collagen, and studied their expression profiles in regenerating limbs of newts, Cynops pyrrhogaster . The expression of the α1(I) gene was markedly up‐regulated at the early bud stage of the blastema. In situ hybridization experiments revealed that the α1(I) gene was expressed in not only mesenchymal cells of the blastema, but also the basal cells of the wound epidermis at the wound healing stage when the epidermal basement membrane was absent. This unique expression continued until 21 days (late bud stage), while the basement membrane began to form at 14 days. These results indicate biochemical differences between the wound and normal epidermis, and suggest the direct involvement of the former in the synthesis of blastemal matrices of type I collagen. Actually, immunohistochemistry revealed that type I collagen began to be deposited beneath the wound epidermis at 8 days, and accumulated there and around blastemal mesenchymal cells at 14 to 21 days. Undifferentiated mesenchymal cells associated with the amputated muscle fibers actively expressed the α1(I) gene. Mesenchymal cells in the central region of blastemas deposited type I collagen fibers around them. Concomitantly with the appearance of prechondrocytes, the α1(II) collagen gene became activated. The present study clearly shows that the expression of the genes of both type I and type II collagen in blastemal cells is temporally and regionally well‐regulated in a cooperative manner. Dev Dyn 1999;216:59–71. © 1999 Wiley‐Liss, Inc.