Figure 4.

The mus81 send1 Phenotypes Are RAD51 Independent.

(A) The growth defects of mus81 send1 plants (left image) are not suppressed by the absence of RAD51 (middle image) nor by expression of the dominant-negative RAD51-GFP (right image). A 2-cm scale bar is shown at the bottom right.

(B) to (I) DAPI-stained meiotic nuclei. Normal meiotic progression can occur in mus81 send1 pollen mother cells, with complete synapsis at pachytene (B), five intact bivalents at metaphase I (C), two pools of five chromosomes at metaphase II (D), and tetrads with four balanced meiotic products (E). Meiotic chromosome segregation defects were occasionally observed in these plants (telophase I; [F]), leading to unbalanced pools of chromosomes at metaphase II (G) and aberrant telophase II tetrads with chromosome bridges (arrow; [H] and [I]). Bars = 10 µm.