ISSN:
0192-253X
Keywords:
Somatic embryogenesis
;
gene regulation
;
transgenic plants
;
β-glucuronidase
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Extensive studies of gene expression programs in carrot somatic embryos identified a gene, designated Dc3, that serves as a reliable molecular marker for the acquisition of embryogenic potential by carrot cells in culture. The complete sequence of a carrot genomic region, DcG3, encoding a Dc3-like mRNA, was determined. The DcG3 transcription unit contains a single intron and encodes mRNA that is expressed at high levels in embryonic tissue but is undetectable in somatic tissue of carrot. The predicted protein sequence of DcG3 is 163 amino acids and includes two approximately 50 amino acid direct repeats which in turn include additional repetitive elements with an unusual distribution of charged amino acids. Dc3 and Dc3-like mRNAs are encoded by a small divergent gene family. Furthermore, similarities of the Dc3 gene family with genes from other plant species that are expressed in response to environmental and developmental cues suggest a possible role in seed desiccation and possibly in more general water-stiess responses in plants. Analysis of transgenic tobacco containing a β-glucuronidase (GUS) reporter gene fused to a 1.7 kb 5′ upstream element of DcG3 defined a promoter/enhancer complex that confers developmentally and environmentally regulated expression of GUS activity. Thus, DcG3 is phylogenetically conserved together with the trans-acting factors required for its regulated expression in transgenic tobacco.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/dvg.1020110108
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