YCL007C was assigned the gene name CWH36 based on the calcofluor white hypersensitivity phenotype of mutants in this ORF (2, 3). However, more recently it has been shown (1) that the calcofluor white hypersensitivity phenotype actually corresponds to the overlapping ORF, YCL005W-A, on the Watson strand. YCL005W-A, an intron containing ORF, was added to SGD in July of 2003, based on comparison with the Ashbya genome (4) and did not exist in SGD when the CWH phenotype data were published in 1997. There is an 87% overlap of sequence between YCL007C and YCL005W-A. The following results from Davis-Kaplan et al. (1) unambiguously prove that YCL005W-A is the open reading frame that is transcribed and confers the CWH phenotype:

1. Disruption of YCL005W-A alone (leaving YCL007C intact) confers calcofluor white hypersensitivity that is not complemented by expression of YCL007C under control of the MET3 promoter.
2. S1 nuclease analysis indicates that the Watson strand ORF is transcribed
3. YCL005W-A is apparently transcribed into poly(A)-mRNA, based on RT-PCR amplification using poly dT primer and a YCL005W-A exon II-specific probe.

In light of the evidence in Davis-Kaplan et al. (1) and in consultation with the authors who published on YCL007C/CWH36, SGD has made CWH36 an alias name for YCL007C and changed the ORF designation to Dubious. CWH36 will also remain an alias name for YCL005W-A.

Last updated: 2004-02-24

1)	Davis-Kaplan SR, et al.  (2004) Genome-wide analysis of iron-dependent growth reveals a novel yeast gene required for vacuolar acidification. J Biol Chem 279(6):4322-9
2)	Ram AF, et al.  (1994) A new approach for isolating cell wall mutants in Saccharomyces cerevisiae by screening for hypersensitivity to calcofluor white. Yeast 10(8):1019-30
3)	Lussier M, et al.  (1997) Large scale identification of genes involved in cell surface biosynthesis and architecture in Saccharomyces cerevisiae. Genetics 147(2):435-50
4)	Brachat S, et al.  (2003) Reinvestigation of the Saccharomyces cerevisiae genome annotation by comparison to the genome of a related fungus: Ashbya gossypii. Genome Biol 4(7):R45