ATP16 Genes and Neighboring ORFs Are Duplicated on Chromosome IV in Saccharomyces cerevisiae

We present evidence that there were two closely linked copies of the ATP16 (YDL004w) gene encoding the delta subunit of F1F0-ATPase complex on chromosome IV in laboratory strains, W303-1A, W303-1B, DC5, LL20, SEY2102, YPH499, and S288C of Saccharomyces cerevisiae. We previously reported that there were 2-3 copies of ATP1 (alpha), ATP2 (beta) and ATP3 (gamma) on chromosomes II, X, and II, respectively. Homologous recombination of the ATP16 with HIS3 (YOR202w), gene walking, and long-PCR analyses showed that two ATP16 were present on the same chromosome as above genes. The gene walking estimated that the two ATP16 were separated by approximately 8.4 kb using ATP16 and its neighboring DNAs as probes, designated the proximal ATP16 to the telomere as ATP16a and to the distal as ATP16b. Although the nucleotide sequences of ATP16a and ATP16b were identical including 833 bases upstream- and 937 bases downstream of ATP16, they might be expressed differently.