Chromosome XV was one of the last two chromosomes of Saccharomyces cerevisiae to be discovered. It is the third-largest yeast chromosome after chromosomes XII and IV, and is very similar in size to chromosome VII. It alone represents 9% of the yeast genome (8% if ribosomal DNA is included). When systematic sequencing of chromosome XV was started, 93 genes or markers were identified, and most of them were mapped. However, very little else was known about chromosome XV which, in contrast to shorter chromosomes, had not been the object of comprehensive genetic or molecular analysis. It was therefore decided to start sequencing chromosome XV only in the third phase of the European Yeast Genome Sequencing Programme, after experience was gained on chromosomes III, XI and II. The sequence of chromosome XV has been determined from a set of partly overlapping cosmid clones derived from a unique yeast strain, and physically mapped at 3.3-kilobase resolution before sequencing. As well as numerous new open reading frames (ORFs) and genes encoding tRNA or small RNA molecules, the sequence of 1,091,283 base pairs confirms the high proportion of orphan genes and reveals a number of ancestral and successive duplications with other yeast chromosomes.
A 54,719 bp fragment from the right arm of Saccharomyces cerevisiae chromosome XV has been sequenced from the inserts of two cosmids (pEOA213 and pEOA217). The computer analysis of this sequence has revealed the presence of eight known genes (CKA2, CYC1, ALG8, TCM1, TMP1, UFE1, RTS2 and ASE1) and four open reading frames (ORFs) with strong homologies with known yeast genes (MLP1, SIS2 and HBS1 and the allantoin permease). The characteristics of the other ORFs and of the corresponding proteins do not allow postulation of a precise function. Several have features reminiscent of cytoskeleton or motor elements (keratin-like, myosin-like) and several others have characteristics of proteins which interact with DNA (extremely basic, b-Zip structure and/or acidic domains). Two tRNAs (tRNA(Lys) and tRNA(Pro)) have also been identified on this fragment. Many of these ORFs present similarities with ORFs located on chromosome XI, indicating some information reshuffling between the two chromosomal fragments.
The complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome XI has been determined. In addition to a compact arrangement of potential protein coding sequences, the 666,448-base-pair sequence has revealed general chromosome patterns; in particular, alternating regional variations in average base composition correlate with variations in local gene density along the chromosome. Significant discrepancies with the previously published genetic map demonstrate the need for using independent physical mapping criteria.
        
Title: DNA sequence analysis of a 17 kb fragment of yeast chromosome XI physically localizes the MRB1 gene and reveals eight new open reading frames, including a homologue of the KIN1/KIN2 and SNF1 protein kinases Pallier C, Valens M, Puzos V, Fukuhara H, Cheret G, Sor F, Bolotin-Fukuhara M Ref: Yeast, 9:1149, 1993 : PubMed
We report in this paper the sequence of a part of chromosome XI of Saccharomyces cerevisiae. This 17 kbp nucleotide sequence represents the right half of cosmid pUKG151 and contains nine open reading frames, YKL453, 450, 449, 448, 445, 443, 442, 441 and the 5' part of YKL440. YKL440 was previously identified as the MBR1 gene and plays a role in mitochondrial biogenesis. YKL443 is a homologue of the yeast serine-rich protein (SRP1), while YKL453 presents strong homologies with the KIN1/KIN2/SNF1 kinase family. It must be pointed out that the size of this gene is well above average for yeast.