Histone acetylation and chromatin remodeling are required for UV-B-dependent transcriptional activation of regulated genes in maize.
The nuclear proteomes of maize (Zea mays) lines that differ in UV-B tolerance were compared by two-dimensional gel electrophoresis after UV light treatment. Differential accumulation of chromatin proteins, particularly histones, constituted the largest class identified by mass spectrometry. UV-B-tolerant landraces and the B73 inbred line show twice as many protein changes as the UV-B-sensitive b, pl W23 inbred line and transgenic maize expressing RNA interference constructs directed against chromatin factors. Mass spectrometic analysis of posttranslational modifications on histone proteins demonstrates that UV-B-tolerant lines exhibit greater acetylation on N-terminal tails of histones H3 and H4 after irradiation. These acetylated histones are enriched in the promoter and transcribed regions of the two UV-B-upregulated genes examined; radiation-sensitive lines lack this enrichment. DNase I and micrococcal nuclease hypersensitivity assays indicate that chromatin adopts looser structures around the selected genes in the UV-B-tolerant samples. Chromatin immunoprecipitation experiments identified additional chromatin factor changes associated with the nfc102 test gene after UV-B treatment in radiation-tolerant lines. Chromatin remodeling is thus shown to be a key process in acclimation to UV-B, and lines deficient in this process are more sensitive to UV-B.
Casati
Paula
P
Centro de Estudios Fotosintéticos y Bioquímicos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000 Rosario, Argentina. casati@cefobi.gov.ar
Campi
Mabel
M
Chu
Feixia
F
Suzuki
Nagi
N
Maltby
David
D
Guan
Shenheng
S
Burlingame
Alma L
AL
Walbot
Virginia
V
D000107:Acetylation; D001483:Base Sequence; D002843:Chromatin / Q000378:metabolism*; D017931:DNA Primers; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D006657:Histones / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D015533:Transcriptional Activation / Q000528:radiation effects*; D014466:Ultraviolet Rays; D003313:Zea mays / Q000235:genetics / Q000528:radiation effects*
D002843:Chromatin; D017931:DNA Primers; D006657:Histones