Regulation of Arabidopsis shoot apical meristem and lateral organ formation by microRNA miR166g and its AtHD-ZIP target genes.
Plant development is characterized by precise control of gene regulation, leading to the correct spatial and temporal tissue patterning. We have characterized the Arabidopsis jabba-1D (jba-1D) mutant, which displays multiple enlarged shoot meristems, radialized leaves, reduced gynoecia and vascular defects. The jba-1D meristem phenotypes require WUSCHEL (WUS) activity, and correlate with a dramatic increase in WUS expression levels. We demonstrate that the jba-1D phenotypes are caused by over-expression of miR166g, and require the activity of the RNase III helicase DCL1. miR166g over-expression in jba-1D plants affects the transcripts of several class III homeodomain-leucine zipper (AtHD-ZIP) family target genes. The expression of PHABULOSA (PHB), PHAVOLUTA (PHV) and CORONA (CNA) is significantly reduced in a jba-1D background, while REVOLUTA (REV) expression is elevated and ATHB8 is unchanged. In addition, we show that miR166 has a dynamic expression pattern in wild-type and jba-1D embryos. Our analysis demonstrates an indirect role for miRNAs in controlling meristem formation via regulation of WUS expression, and reveals complex regulation of the class III AtHD-ZIP gene family.
Williams
Leor
L
Plant Gene Expression Center, USDA/UC Berkeley, 800 Buchanan Street, Albany, CA 94710, USA.
Grigg
Stephen P
SP
Xie
Mingtang
M
Christensen
Sioux
S
Fletcher
Jennifer C
JC
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D018519:Meristem / Q000502:physiology*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D010641:Phenotype; D016415:Sequence Alignment
D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D035683:MicroRNAs; C116421:WUSCHEL protein, Arabidopsis