A. thaliana has two orthologs of the yeast ribosome biogenesis factor Brx1. (A) A schematic alignment of atBRX1-1, atBRX1-2, and scBRX1 is shown. Negatively and positively charged amino acids are colored in red and blue, respectively. Note that both atBRX1 proteins have a charged amino-terminal insertion. (B) The expression of BRX1-1 and BRX1-2 mRNAs at the indicated developmental stages was analyzed by qRT-PCR. The results are the mean of four independent biological replicates and standard deviation is shown. By t-test no change with P < 0.05 was observed. (Seeds imb) Imbibed seeds. (C) Total proteins were extracted from the tissues and at the developmental stages indicated, separated on SDS-PAGE and subjected to Western blot using atBRX1 (top) and atRPL5 (bottom) antibodies. Arrowheads on the right indicate the migration of atBRX1-1 (filled) and atBRX1-2 (open). The intensity of detected bands was analyzed and the ratio of atBRX1-2 to atBRX1-1 and total atBRX1 to atRPL5, normalized to day 5, is indicated. (cc) Cell culture.
