Figure 5.

Auxin control of the miR167 level. (A) Decrease of the miR167 level in cells growing in the auxin-free medium. The levels of miR167 in cells harvested at the first and second days following the growth in medium containing 9 μM of 2,4-D (left two lanes) and in cells harvested 1–3 days following the transfer of cells from the auxin-containing medium to the auxin-free medium (right three lanes). (B) Changes of the miR167 level following transfer between auxin⁺ and auxin⁻ media. Cells growing on auxin⁺ medium were transferred to auxin⁻ medium, and measured miR167 at the designated times following the transfer (left six auxin⁻ columns). These cells grown on auxin^- medium for 24 h were transferred to auxin⁺ medium to measure miR167 at the designated times (the three auxin⁺ columns). These cells grown on auxin⁺ medium for 12 h were transferred back to aux⁻ medium and measured miR167 at 12 h after transfer (right auxin^- column). (C) Auxin-concentration effects on the miR167 level. The miR167 levels were measured in cells growing for 24 h on the medium containing the designated concentrations of 2,4-D. (D) Auxin control of cleavage of ARF8 mRNA and of OsGH3-2 expression. (Left column) While ARF8 mRNA remained intact in cells grown in auxin-free medium (right lane), they were efficiently cleaved in cells grown in auxin-containing medium (left lane). (Right column) Northern blot analyses of the expression of the OsGH3-2 gene in cells growing in auxin-free medium (right three lanes) and in auxin-containing medium (left two lanes). The strongest OsGH3-2 signal is shown in cells grown for three days in auxin-free medium.