Figure 5.

Northern-blot analysis of expression of the Cs1-MMP gene. RNA isolated from different developmental stages of cucumber cotyledon (A) and leaf discs (B) were hybridized with the partial Cs1-MMP cDNA (top panel) and the maize Ubi cDNA as a control (bottom panel). Arrows indicate sizes of the transcripts. A, Cotyledons were harvested at the indicated stages as previously described in Figure 1. B, Leaves in which all the cells were at a similar stage of senescence were rare so discs were excised from regions of the leaf where cells were of a uniform color. Stage II refers to RNA isolated from discs excised from fully expanded green leaves from young plants. Stage III refers to RNA isolated from discs excised from mature green leaves isolated from plants that had started flowering. Stages IV and V refer to RNA isolated from discs excised from regions of senescing leaves showing 65% and 35% of green leaf chlorophyll levels, respectively. Stage VI refer to RNA isolated from leaf discs excised from yellow regions. Stage VII refer to RNA isolated leaf discs excised from dead (brown) regions.