CEFOBI   05405
CENTRO DE ESTUDIOS FOTOSINTETICOS Y BIOQUIMICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
ROLE OF CHROMATIN REMODELING PROTEINS IN THE UV-B RESPONSE OF PLANTS
Autor/es:
CAMPI M.; EMILIANI J.; CASATI P.
Lugar:
Mar del plata
Reunión:
Congreso; XLIII Reunión Annual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2007
Resumen:
ROLE OF CHROMATIN REMODELING PROTEINS IN THE
UV-B RESPONSE OF PLANTS
Campi, Mabel; Emiliani, Julia; Casati,
Paula. CEFOBI.
Fac.
Cs. Bioq. y Farm. UNR. Suipacha 531. 2000.Rosario.
Argentina.
e-mail:campi@cefobi.gov.ar
UV-B
radiation affects plant development and physiology. UV-B causes the formation
of photoproducts in DNA, which affects the structural and dynamic properties of
chromatin. In maize, genes encoding chromatin remodeling proteins are regulated
by UV-B, including chc101, nfc 102 and sdg102. A. thaliana chc1,
nfc4 and sdg26 genes are the homologues
to those from maize; we measured mRNA levels after 4 h-UV-B exposure:
transcripts are induced for all genes. To investigate the role of each protein
in UV-B responses, T-DNA mutants and RNAi plants were analyzed; they show null or decreased
transcript levels compared to WT plants. Flavonoid levels increased in WT
plants by UV-B (54%). However, chc101
deficient plants showed a smaller increase (24%); while in nfc 102 and sdg10, flavonoids
are unchanged. Thus, these plants have altered regulation of UV sunscreen
accumulation. Chlorophyll levels also varied among lines: chc1 mutants showed
a decrease of 55% by UV-B, while WT, sdg26 and nfc4 deficient
plants show unchanged chl levels by UV-B. However, although preliminary, CO2
fixation in sdg26 mutants seems
to be more affected by UV-B than in WT plants. Together, Arabidopsis plants
with null or decreased levels of transcripts encoding chromatin remodeling
factors exhibit increased UV-B sensitivity. DNA
damage and UV-B regulation of marker genes in these plants are under study.