PMC

FLP activity in C. albicans strains S2FI1 and S2FI5B carrying chromosomally integrated caFLP and ecaFLP genes, respectively, under control of the SAP2 promoter. Cells were grown overnight in SAP2-repressing minimal medium and inoculated into SAP2-inducing medium YCB-BSA. FLP-mediated excision of the MPA^R marker was analyzed by determining the percentage of MPA^S cells at the indicated times.

Structure of the insert in plasmid pSFL213 carrying the SAP2P-ecaFLP fusion. Relevant restriction sites used for cloning are shown. C, ClaI; E, EcoRI; H, HindIII; P, PstI; S, SalI; Sc, SacI; Sp, SpeI; V, EcoRV; X, XbaI. For the construction of analogous fusions with other SAP genes, the corresponding fragments were substituted for the flanking SAP2P and 3′SAP2 regions (see Materials and Methods).

Differential activation of SAP genes after hematogeneous dissemination. For each of the reporter strains, three mice were i.v.-infected with 4 × 10⁵ cells (A) and three mice with 2 × 10⁵ cells (B). SAP activation was determined in cells recovered from the kidneys after 4 days of infection. Strains are as described in the legend to Fig. .

Stage-specific induction of individual SAP genes during the course of i.p. infection. For each of the reporter strains, two mice were infected i.p., and SAP activation was determined in cells recovered by peritoneal lavage 30 min after inoculation (A), in cells adhering to the tissue after 4 h of infection (B), and in cells that had invaded the liver (C) or disseminated to the kidneys (D) after 48 h of infection. Strains are as described in the legend to Fig. .

Expression of individual SAP genes during oesophageal infection. For each of the reporter strains, two mice were orally infected, and C. albicans cells that had invaded the oesophageal epithelium were reisolated from homogenized tissue after 3 days of infection. Activation of the SAP genes in the reporter strains was analyzed by determining the percentage of MPA^S cells. The light gray columns show SAP induction in strains S1FI2A, S2FI5B, S3FI2B, S4FI2A, S5FI2A, and S6FI2A, and the dark gray columns show the results obtained with S1FI2B, S2FI5G, S3FI2C, S4FI2B, S5FI2B, and S6FI2B.

Construction of C. albicans reporter strains carrying chromosomally integrated fusions of the promoter regions of SAP1-SAP6 with ecaFLP. (A–F) Southern hybridizations of BglII-digested genomic DNA with the promoter fragments of the SAP1–SAP6 genes as probes. To distinguish between integration into either of the two SAP1 and the two SAP2 alleles, KpnI (G) and ClaI (H), digested DNA of the corresponding strains was used additionally. The fragments representing the wild-type SAP alleles are indicated in bold letters on the left side of the blots; the crosshybridizing SAP4, SAP5, and SAP6 alleles also are indicated. The sizes of the wild-type fragments and those containing the reporter fusions are shown on the right side of the blots. Lanes: 1, CFI1 (parent strain); 2, S1FI2A (sap1-2∷SAP1P-ecaFLP); 3, S1FI2B (sap1-1∷SAP1P-ecaFLP); 4, S2FI5B (sap2-1∷SAP2P-ecaFLP); 5, S2FI5G (sap2-2∷SAP2P-ecaFLP); 6, S3FI2B (sap3∷SAP3P-ecaFLP); 7, S3FI2C (sap3∷SAP3P-ecaFLP); 8, S4FI2A (sap4-2∷SAP4P-ecaFLP); 9, S4FI2B (sap4-1∷SAP4P-ecaFLP); 10, S5FI2A (sap5-1∷SAP5P-ecaFLP); 11, S5FI2B (sap5-2∷SAP5P-ecaFLP); 12, S6FI2A (sap6∷SAP6P-ecaFLP); 13, S6FI2B (sap6∷SAP6P-ecaFLP).