Livant, Donna L. and Hough-Evans, Barbara R. and Moore, James G. and Britten, Roy J. and Davidson, Eric H. (1991) Differential stability of expression of similarly specified endogenous and exogenous genes in the sea urchin embryo. Development, 113 (2). pp. 385-398. ISSN 0950-1991 http://resolver.caltech.edu/CaltechAUTHORS:LIVdev91
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The object of these experiments was to determine whether competitive titration in vivo of factors required for expression of the CyIIIa·CAT fusion gene would affect expression of the endogenous CyIIIa gene in the same embryos. Earlier work showed that expression of this fusion gene after injection into sea urchin eggs is stoichiometrically reduced when low molar excesses of DNA fragments containing only its regulatory domain are coinjected. In order to compare endogenous (i.e. CyIIIa) and exogenous (i.e. CyIIIa·CAT) expression simultaneously in embryos bearing excess competitor regulatory DNA, we developed, and here describe, a new procedure for generating transgenic sea urchin embryos in which all of the cells in many embryos, and most in others, bear the exogenous DNA. Such large reduction of mosaicism can be achieved by multiple injection of the exogenous DNA fragments into fertilized eggs. Using this method, we demonstrate that at a level of competitor DNA incorporation which reduces CyIIIa·CAT expression by 85%, endogenous CyIIIa mRNA levels are wholly unaffected. Nor is spatial expression of the endogenous CyIIIa gene disturbed. Since the CyIIIa·CAT genes are properly expressed under control of the CyIIIa regulatory sequences, they must participate in the same set of necessary DNA-protein interactions. However, we infer from the results that we report here that the regulatory complexes in the endogenous CyIIIa gene are greatly stabilized relative to those of the exogenous CyIIIa·CAT genes.
|Additional Information:||Copyright © 1991 by Company of Biologists. (Accepted 27 June 1991) This work was supported by an NIH Grant (HD-05753) and by a Developmental Biology Grant from the Lucille P. Markey Charitable Trust.|
|Subject Keywords:||in vivo competition, commitment, specification, gene transfer, gene regulation in early development|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Archive Administrator|
|Deposited On:||03 Sep 2008 23:00|
|Last Modified:||26 Dec 2012 10:15|
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