RRC ID 60881
Author Plante S, Labbé S.
Title Spore Germination Requires Ferrichrome Biosynthesis and the Siderophore Transporter Str1 in Schizosaccharomyces pombe.
Journal Genetics
Abstract Spore germination is a process whereby spores exit dormancy to become competent for mitotic cell division. In Schizosaccharomyces pombe, one critical step of germination is the formation of a germ tube that hatches out the spore wall in a stage called outgrowth. Here, we show that iron deficiency blocks the outgrowth of germinating spores. The siderophore synthetase Sib1 and the ornithine N5-oxygenase Sib2 participate in ferrichrome biosynthesis, whereas Str1 functions as a ferrichrome transporter. Expression profiles of sib1+ , sib2+ , and str1+ transcripts reveal that they are induced shortly after induction of germination and their expression remains upregulated throughout the germination program under low-iron conditions. sib1Δ sib2Δ mutant spores are unable to form a germ tube under iron-poor conditions. Supplementation with exogenous ferrichrome suppresses this phenotype when str1+ is present. Str1 localizes at the contour of swollen spores 4 hr after induction of germination. At the onset of outgrowth, localization of Str1 changes and it moves away from the mother spore to primarily localize at the periphery of the new daughter cell. Two conserved Tyr residues (Tyr553 and Tyr567) are predicted to be located in the last extracellular loop region of Str1. Results show that these amino acid residues are critical to ensure timely completion of the outgrowth phase of spores in response to exogenous ferrichrome. Taken together, the results reveal the essential requirement of ferrichrome biosynthesis to promote outgrowth, as well as the necessity to take up ferrichrome from an external source via Str1 when ferrichrome biosynthesis is blocked.
Volume 211(3)
Pages 893-911
Published 2019-3-1
DOI 10.1534/genetics.118.301843
PII genetics.118.301843
PMID 30647069
PMC PMC6404258
MeSH Cation Transport Proteins / chemistry Cation Transport Proteins / genetics Cation Transport Proteins / metabolism* Ferrichrome / metabolism* Iron / metabolism Protein Domains Protein Transport Schizosaccharomyces / genetics* Schizosaccharomyces / physiology Schizosaccharomyces pombe Proteins / chemistry Schizosaccharomyces pombe Proteins / genetics Schizosaccharomyces pombe Proteins / metabolism* Spores, Fungal / genetics*
IF 3.564
Times Cited 1
Yeast FY12806