INVESTIGADORES
WELCHEN Elina
artículos
Título:
The promoter of the Arabidopsis nuclear gene COX5b-1, encoding subunit 5b of the mitochondrial cytochrome c oxidase, directs tissue-specific expression by a combination of positive and negative regulatory elements
Autor/es:
WELCHEN, ELINA.; CHAN, RAQUEL L.; GONZALEZ, DANIEL H.
Revista:
JOURNAL OF EXPERIMENTAL BOTANY
Editorial:
Society for Experimental Biology
Referencias:
Año: 2004 p. 1997 - 2004
ISSN:
0022-0957
Resumen:
In the present work, the promoter of the Arabidopsis
thaliana nuclear gene COX5b-1, encoding subunit 5b of
the mitochondrial cytochrome c oxidase, has been
analysed. For this purpose, plants, stably transformed
with different promoter fragments fused to the bglucuronidase
reporter gene, have been obtained. Histochemical
staining indicated that the COX5b-1 promoter
directs expression in meristems and in vascular tissues
of cotyledons, roots, and hypocotyls, as well as in
anthers and pollen and the central leaf vein. Quantitative
measurements in extracts prepared from different
organs suggested that expression is higher in roots.
The analysis of progressive upstream deletions of the
promoter suggested the presence of negative regulatory
elements, preferentially active in leaves, between
nucleotides 2609 and 2387 from the translation start
site. A further deletion down to nucleotide 2195 completely
abolished expression. The inclusion of sucrose
or the cytokinin 6-benzylaminopurine in the culture
medium induced COX5b-1 promoter-dependent bglucuronidase
expression. This induction was observed
with all constructs that produced b-glucuronidase activity.
Putative regulatory elements involved in the
regulation of other genes were detected in the promoter
fragment required for expression. A detailed analysis of
these elements will help to elucidate the molecular
mechanisms that participate in the expression of this
and, possibly, other components of the cytochrome cdependent
respiratory pathway.