Homologous recombination partly restores the secretion defect of underglycosylated acid phosphatase in yeast.
The majority of secreted acid phosphatase in Saccharomyces cerevisiae is encoded by the PH05 gene. The secretion level of this acid phosphatase is directly determined by its level of glycosylation. Consequently, PHO5-11-encoded acid phosphatase which lacks 11 of 12 glycosylation sites is only poorly secreted. We have isolated and characterized both UV- and EMS-induced variants, which are partly able to restore the secretion of acid phosphatase. Our data indicate that the improved secretion is caused by mitotic intrachromosomal recombination between the PHO5-11 allele and the homologous tandemly repeated PHO3 sequences, resulting in the restoration of glycosylation sites in PHO5-11. Two different recombination mechanisms, unequal sister-chromatid exchange and sister-chromatid gene conversion, are responsible for these alterations of the PHO5-11 locus. Thus, recombination between mutant and wild-type sequences are able to restore the ability of mutant yeast cells to secrete acid phosphatase.
Praetorius-Ibba
M
M
Ciba-Geigy Ltd., Department of Core Drug Discovery Technologies, Basel, Switzerland. mette@trna.chem.yale.edu
Monnet
G
G
Meyhack
B
B
Kielland-Brandt
M
M
Nilsson-Tillgren
T
T
Hinnen
A
A
D000135:Acid Phosphatase / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D005800:Genes, Fungal; D014644:Genetic Variation; D006031:Glycosylation; D026901:Membrane Transport Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D028061:Phosphate Transport Proteins; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D028061:Phosphate Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C026989:thiamine-binding protein; C055831:phosphate permease; D000135:Acid Phosphatase; C488913:PHO3 protein, S cerevisiae; C488916:PHO5 protein, S cerevisiae