Figure 8. Synaptonemal complex formation and sporulation in ndj1Δ/csm4Δ mutants.

A) Meiotic progression, as measured by the formation of synaptonemal complex (SC). Meiotic progression was monitored in strains where the SC was illuminated by Zip1-GFP(700) (for details, see [2],[6]). i The various steps of SC formation are shown for a WT strain (NKY3834): after diffuse fluorescence, dots appear that correspond to formation of DSBs. Later, short lines correspond to the zygotene onset, whereas at the pachytene stage SC appears as linear, contiguous ribbons. ii For WT, ndj1Δ, ndj1Δ csm4Δ, and csm4Δ strains (NKY3834, NKY3837, NKY4003, and NKY4002, respectively), fixed nuclei where examined at hourly intervals and scored for zygotene (triangle symbol) or pachytene (square symbol) categories. The proportions of nuclei within one or the other categories are plotted as a function of time in SPM. Completion of MI (MI+MII) for each time course is indicated by a dotted line curve. iii zygotene and pachytene lifespan as deduced from the cumulative curve analysis for WT and ndj1Δ, and csm4Δ mutants. iv Cumulative curve analysis of zygotene and pachytene progression. The upper two panels indicate zygotene and pachytene for WT (top) and csm4Δ (bottom). The lower two panels show the onset of zygotene (top) and pachytene (bottom) for all strains. Color code is the same as in ii. v For WT, ndj1Δ, ndj1Δ csm4Δ, and csm4Δ strains, differences between the time when 50% of the nuclei have progressed through MI and the time when 50% have exited pachytene. B) Meiotic progression, as measured by completion of MI divisions in WT (NKY3834), and in ndj1Δ and csm4Δ mutants without (full symbols, upper panel; strains NKY3837 and NKY4002, respectively) and with the spo11-Y135F mutation (empty symbols, lower panel; strains NKY3907 and NKY3908, respectively). All scale bars represent 2 µm.