英语翻译Temporal regulation of shoot development in Arabidopsist

英语翻译
Temporal regulation of shoot development in Arabidopsis
thaliana by miR156 and its target SPL3
Gang Wu and R.Scott Poethig*
SPL3,SPL4 and SPL5 (SPL3/4/5) are closely related members of the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE family of
transcription factors in Arabidopsis,and have a target site for the microRNA miR156 in their 3\2 UTR.The phenotype of Arabidopsis
plants constitutively expressing miR156-sensitive and miR156-insensitive forms of SPL3/4/5 revealed that all three genes promote
vegetative phase change and flowering,and are strongly repressed by miR156.Constitutive expression of miR156a prolonged the
expression of juvenile vegetative traits and delayed flowering.This phenotype was largely corrected by constitutive expression of a
miR156-insensitive form of SPL3.The juvenile-to-adult transition is accompanied by a decrease in the level of miR156 and an
increase in the abundance of SPL3 mRNA.The complementary effect of hasty on the miR156 and SPL3 transcripts,as well as the
miR156-dependent temporal expression pattern of a 35S::GUS-SPL3 transgene,suggest that the decrease in miR156 is responsible
for the increase in SPL3 expression during this transition.SPL3 mRNA is elevated by mutations in ZIPPY/AGO7,RNA DEPENDENT
RNA POLYMERASE 6 (RDR6) and SUPPRESSOR OF GENE SILENCING 3 (SGS3),indicating that it is directly or indirectly regulated by
RNAi.However,our results indicate that RNAi does not contribute to the temporal expression pattern of this gene.We conclude
that vegetative phase change in Arabidopsis is regulated by an increase in the expression of SPL3 and probably also SPL4 and SPL5,
and that this increase is a consequence of a decrease in the level of miR156.
KEY WORDS:miRNA,Heterochrony,Phase change
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