INVESTIGADORES
VIOLA Ivana Lorena
congresos y reuniones científicas
Título:
Analysis of binding properties of BLH3-STM heterodimers and the individual proteins with DNA.
Autor/es:
IVANA VIOLA; DANIEL H. GONZALEZ
Lugar:
Mar del Plata, Buenos Aires, Argentina.
Reunión:
Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular, SAIB.; 2007
Institución organizadora:
SAIB
Resumen:
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Plant TALE homeodomain (HD) proteins
from the KNOX and BEL families interact through conserved domains present in
the N-terminal portion of the respective proteins. In the present study, we
have analyzed the interaction of the complex formed by the Arabidopsis proteins
STM (KNOX) and BLH3 (BEL) with DNA sequences containing one or two binding
sites. EMSA assays indicate that complex formation produces an increase in
binding affinity for both types of sequences. However, missing nucleoside
experiments suggest that this is not related with the establishment of new
detectable contacts. In addition, site-directed mutants in the HD indicated
that only one functional homeodomain is required for high affinity DNA binding.
In vivo DNA binding assays using the
yeast one-hybrid system showed that the complex is able to interact with DNA,
but that sequence-specific differences exist in the interaction of the complex
and individual proteins with DNA that depend on the protein level expression. Moreover,
ATH1 and BEL1 BEL proteins are able to produce complexes with STM that have
similar properties as those observed with BLH3. Taken together, our results reflect
the existence of different regulatory modes by KNOX and BEL proteins, either
alone or in combination, depending on specific sequences present in their
target genes and on the relative concentrations of the two proteins within the
cell.