INVESTIGADORES
GONZALEZ Daniel Hector
artículos
Título:
Genes encoding cytochrome c oxidase subunit 5c from sunflower (Helianthus annuus L.) are regulated by nitrate and oxygen availability
Autor/es:
CURI, GRACIELA C.; CHAN, RAQUEL L.; GONZALEZ, DANIEL H.
Revista:
PLANT SCIENCE
Editorial:
ELSEVIER IRELAND LTD
Referencias:
Lugar: Amsterdam; Año: 2002 vol. 163 p. 897 - 905
ISSN:
0168-9452
Resumen:
Subunit 5c is the smallest subunit of plant cytochrome c oxidases and
has no defined counterpart in animal and fungi. To gain insight about
the function and regulation of its expression, we have isolated two
cDNAs encoding this subunit from a sunflower (Helianthus annuus L.) root
library. The encoded proteins are 91% identical at the amino acid
level. Northern blots using specific probes indicated that both genes
have similar expression patterns, with higher transcript levels in
non-photosynthetic tissues. According to in situ hybridization
experiments, expression in roots is localized within developing cortex
and vascular tissues, with relatively low levels in the root cap and
epidermis. Treatment of plants with solutions containing different
nitrate concentrations produced an increase in transcript levels in
roots and leaves. Light and/or sugars produced no significant changes in
expression. Transcript levels were severely reduced upon incubation
under hypoxia, and recovered to initial levels when plants were returned
to normoxic conditions. A similar behavior was observed for the
cytochrome c gene. We conclude that nitrate and oxygen are important
factors regulating the expression of this cytochrome oxidase subunit,
which is only partially coordinated with the expression of other
components of the cyanide-sensitive respiratory pathway.