Livant, Donna L. and Cutting, Ann E. and Britten, Roy J. and Davidson, Eric H. (1988) An in vivo Titration of Regulatory Factors Required for Expression of a Fusion Gene in Transgenic Sea Urchin Embryos. Proceedings of the National Academy of Sciences of the United States of America, 85 (20). pp. 7607-7611. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:LIVpnas88
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We report that endogenous regulatory factors mediating expression of a lineage-specific sea urchin embryo gene can be titrated in vivo by introduction of a sufficient molar excess of DNA-binding sites. Thus we obtain an estimate of the quantity of limiting factor(s) required for developmental activation and transcriptional expression, which can be compared with estimates of factor prevalence obtained by measurements in vivo carried out under equilibrium conditions. A fusion construct in which the bacterial gene for chloramphenicol acetyltransferase (CAT; acetyl-CoA:chloramphenicol O3-acetyltransferase, EC 184.108.40.206) is controlled by cis-regulatory elements of the CyIIIa cytoskeletal actin gene (CyIIIa-CAT) was introduced in varying numbers of copies into sea urchin eggs. The activity of the CyIIIa-CAT fusion gene in 24-hr blastula-stage embryos was shown to saturate as the number of exogenous genes was increased. The mean number of CyIIIa-CAT fusion genes per nucleus at which half saturation was obtained was 105 ± 40 (mean ± SD). This result suggests that equilibrium parameters measured earlier in vitro may apply, at least approximately, within the embryo nuclei.
|Additional Information:||Copyright © 1988 by the National Academy of Sciences Contributed by Eric H. Davidson, June 20, 1988 We are pleased to acknowledge the extremely useful critical reviews provided by Drs. Paul Sternberg and Ellen Rothenberg. This work was supported by National Institutes of Health Grant HD-05753. D.L.L. was supported by a National Research Service Award (HD-07257). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.|
|Subject Keywords:||gene transfer; CyIIIa actin gene; regulatory factor; competition in vivo|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Archive Administrator|
|Deposited On:||08 Nov 2006|
|Last Modified:||14 Nov 2014 19:19|
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