Identification of the AtBMI1C mutant and characterization of artificial microRNAi lines.

(A) Genomic architecture of AtBMI1C and position of the mutation in atbmi1c-1. The 5′ or 3′ UTR is represented by a gray bar. Exons are represented by black bars. Introns are represented by black lines. The T-DNA insertion in atbmi1c-1 (SALK_148143) is located in the 5′ UTR of AtBMI1C. Scale bar, 500 bp. (B) Detection of AtBMI1C mRNA in a homozygous atbmi1c-1 T-DNA insertion line by semiquantitative RT-PCR. Total RNA was extracted from the inflorescences of homozygous atbmi1c and wild-type plants. Semiquantitative RT-PCR was performed to amplify the full-length transcript using ACTIN2/7 as an endogenous control. (C) Characterization of AtBMI1C mRNA abundance in AtBMI1C-Rs. Total RNA was extracted from the inflorescences of AtBMI1C-Rs and wild-type plants. Semiquantitative RT-PCR was conducted to amplify the full-length transcript using ACTIN2/7 as an endogenous control. (D) Morphology of the AtBMI1C-Rs, in which AtBMI1C was down-regulated, compared to wild type and AtBMI1C-R12, an amiRNAi line in which the expression of AtBMI1C was almost the same as in wild type. (E) Flowering time in the AtBMI1C-Rs was the same as in wild type. Plants were grown under LD conditions. The number of rosette leaves was determined after bolting.