S5-08
Opaque-2-like Transcriptional Regulatory Gene Mechanism is Present in
Cassava Storage Roots
de Souza C.R.B., E.R.P. de
Almeida, L.J.C.B. Carvalho and E.S. Gander
EMBRAPA-Genetic
Resources and Biotechnology, CP 02372, CEP 70770-900 Sain Parque
Rural, Brazilia, Brazil carvalho@cenargen.embrapa.br
The
central cylinder of the storage root (SR) of cassava comprises
parenchyma cells packed with starch granule and vessels.
Storage proteins are usually not accumulated in this organ,
mainly because it is not a propagation organ like most tubers in other
plants where starch and proteins are accumulated concomitantly during
the organ development. The
Opaque-2 is a bZIP transcriptional regulatory protein that interacts
with the ACGT core element in gene promoters to regulate the level of
transcription of genes in endosperm.
To test the hypothesis that this transcriptional regulatory
mechanism would be present in regulating genes in the storage process of
parenchyma cells in the SR of cassava, we used the compartmentalization
tissue model described in an accompanying paper, together with Opaque-2
gene sequence identification, Opaque-2 like protein detection in SR
protein extract with Opaque-2 specific Ab and specific DNA fragment
recognition by protein
extracted from SR. Results
indicated that the Opaque-2 specific Ab recognized two proteins of 30
kDa and 45kDa molecular weight in SR protein crude extract, and that the
45 kDa protein recognizes the promoter of the gene be2S1
from Brazil nut. Isolation
and cloning of the gene corresponding to this potential regulatory
protein is under way.
This research supported by National
Biotechnology Program (EMBRAPA), and Brazilian Conselho Nacional de
Desenvolvimento Científco e Tecnológico
(CNPq)
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