Figure 4

Transcriptional response of committed cells. (a) Average expression of middle sporulation genes. The repressed group (245 genes) and the insulated group (24 genes) are shown. Note that downregulation of the repressed group is specific to YPD, and is not observed on transfer to YPA (which contains nitrogen and acetate) or glucose (4% solution). (b) Expression pattern of NDT80. Expression patterns in (a) and (b) are shown in log₂ ratios, as in Figure 3, and log₂ fold change in expressionis color-coded according to the bar. (c) A summary of the behavior of all sporulation-induced genes. All genes induced during sporulation were considered. A gene was defined as induced at a certain time point during sporulation if it was upregulated more than twofold in that time as well as in the previous and following hours. The induced genes were classified into three categories, depending on their behavior on transfer to YPD: repressed, induced, and insulated. The 'repressed' category included genes that were downregulated by at least 1.5-fold when transferred compared with their level during sporulation. Similarly, the 'induced' category included genes whose expression was upregulated by at least 1.5-fold on transfer. The 'insulated' group included the genes whose expression remained stable (did not change) upon the transfer (expression after transfer to YPD was less than 1.3-fold relative to sporulation).