Abstract
We have isolated and sequenced a cDNA encoding Xenopus laevis pancreatic trypsin, which has approximately 70% amino acid sequence identity to mammalian trypsinogen. Northern blotting analysis shows that the trypsin gene is activated just before the tadpole starts to feed, reaches peak activity in the swimming tadpole (premetamorphosis), and is then repressed during prometamorphosis, attaining its lowest activity at the climax of metamorphosis. The same gene is then activated again in frogs but to a much lower level. The pattern of the changes in trypsin gene expression is followed by at least two other pancreas-specific genes and marks the remodeling of the pancreas of the animal at metamorphosis. Thyroid hormone, which is the causative agent of metamorphosis, can down-regulate trypsin gene expression prematurely.
Publisher
Cold Spring Harbor Laboratory
Subject
Developmental Biology,Genetics
Reference29 articles.
1. Transient activation of oocyte 5S RNA genes in Xenopus embryos by raising the level of the Trans-acting factor TFIIIA
2. Ausubel, F.M., R. Brent, R.E. Kingston, D.D. Moore, J.G. Seidman, J.A. Smith, and K. Struhl. 1988. Current protocols in molecular biology. Wiley, New York.
3. Barrett, A.J. 1986. An introduction to the proteinases. In Proteinase inhibitors. (ed. A.J. Barrett and G. Salvesen) pp. 3–22. Elsevier, Amsterdam.
4. Effect of Prolactin on Thyroxine-Induced Metamorphosis1
5. Broyles, R.H. 1981. Changes in the blood during amphibian metamorphosis. In Metamorphosis: A problem in developmental biology. (ed. L.I. Gilbert and E. Frieden) pp. 461–490. Plenum Press, New York.
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