Photomicrographs: transverse sections of GUS-stained apices for AGO7 promoter analysis

These photomicrographs of histological sections of stained tissue support a manuscript by Hoyer et al.

Many additional photomicrographs from this and related experiments were taken by JSH, EEH, M. Hassert, and H. Fowler. Email j.s.hoyer@wustl.edu if you have questions or would like to examine this additional data.

Methods text:

Histological GUS assays were essentially as described (Bomblies 2002,  Chitwood et al. 2009,  Strader et al. 2011). Seedlings were collected into ice-cold 90% acetone, incubated at -20 °C for 20 minutes and then room temperature for another 20 minutes. Seedlings were washed twice (5 minutes each) with staining buffer (100 mM sodium phosphate [pH 7],  20% methanol,  0.1% Triton X-100,  1.5 mM ferri- and ferrocyanide).

Staining buffer with 0.5 mg/mL 5-bromo-4-chloro-3-indolyl-beta-d-glucuronic acid (X-Gluc) was vacuum-infiltrated into seedlings on ice for two rounds of 15 minutes each. Samples were then incubated at 37 °C for 20 hours, taken through an ethanol/histoclear series, and infiltrated with Paraplast Plus at 60 °C, before embedding (Bomblies 2002). Tissue sections (10 µm thickness) were mounted on Probe-On Plus slides (Thermo Fisher), deparaffinized with histoclear, and coverslipped. Sections were viewed and photographed with a Leica DM750 microscope and ICC50 HD camera.