Construction of an ordered clone bank and systematic analysis of the whole transcripts of chromosome VI ofSaccharomyces cerevisiae

By comparing sequences of restriction enzyme cleavage sites and their distance data, we sorted 384 lambda phage clones containing segments of chromosome VI of S. cerevisiae and constructed an ordered clone bank for this chromosome. The physical length of this bank is 269.7 kb. The bank contains the entire chromosome including the left telomere, but it is not certain whether it contains the right telomere as well. To estimate the number of genes present on this chromosome, we performed a series of Northern hybridization experiments using 157 restriction enzyme fragments prepared from the bank as hybridization probes and total poly(A)+ RNA from vegetatively growing cells. Thus, 97 distinct transcripts were identified. The relative abundance levels of individual transcripts were measured by comparing their band intensity with that of the RPO41 transcript. It was found that the transcripts from the genes located in the telomeric and centromeric regions are less abundant as compared to those from the genes in the central regions of both arms.