Identification ofSaccharomyces cerevisiaeGenes Conferring Resistance to Quinoline Ring-Containing Antimalarial Drugs

Abstract

To identify genes that can confer resistance to antimalarial drugs in yeast, we transformed the quinidine-sensitive strain CYX247-9A ofSaccharomyces cerevisiae with a yeast genomic library and selected for transformants that grow in the presence of elevated levels of antimalarial drugs. Plasmids were rescued from such clones and were analyzed for the presence of individual open reading frames that can confer drug resistance. Using quinidine as the selective drug, we were able to identify three genes that can cause resistance to antimalarial drugs. Overexpression of the yeast genes CIN5 (a member of the family of bZIP transcription factors), STI1 (a Hsp90 cochaperone), and YOR273c (a member of the major facilitator superfamily of transmembrane transporters) conferred 3.9-, 7.0-, and 4.3-fold resistance to quinidine, respectively, over that of control yeast. Cross-resistance assays determined that STI1also conferred resistance to mefloquine (3.4-fold), whileCIN5 also conferred resistance to mefloquine (9.6-fold) and chloroquine (5.4-fold). Using mefloquine as the selective drug, we determined that overexpression of YBR233w, a member of the hnRNPK family of nuclear RNA binding proteins, conferred resistance to mefloquine (13.5-fold). Expression of the human hnRNPKhomolog of YBR233w in S. cerevisiae also conferred mefloquine resistance, suggesting that homologs of the identified resistance genes may perform similar functions in species other than yeast. Our experiments have identified heretofore unknown pathways of resistance to quinoline ring-containing antimalarial drugs in S. cerevisiae.

The Stress Response Factors Yap6, Cin5, Phd1, and Skn7 Direct Targeting of the Conserved Co-Repressor Tup1-Ssn6 in S. cerevisiae

“…Their binding patterns are highly correlated, targeting 73% to 86% of the same sites, depending on the growth conditions [37]. Cin5 and Yap6 are likely involved in yeast stress response, because overexpression of Cin5 or Yap6 increases tolerance to sodium, lithium, and cisplatin [27], [38], and overexpression of Cin5 confers resistance to quinidine, mefloquine, and chloroquine [39]. While these proteins are often considered transcriptional activators, there is evidence that many of them also have repressive functions.…”

Yeast toxicogenomics: genome-wide responses to chemical stresses with impact in environmental health, pharmacology, and biotechnology

“…Yeast has also been used as model for mechanistic studies with other antimalarial drugs, namely mefloquine (Delling et al, 1998), chloroquine (Emerson et al, 2002), artemisinins (Li et al, 2005; Alenquer et al, 2006), and quinidine (Delling et al, 1998; Nunes et al, 2001; Felder et al, 2002; Tenreiro et al, 2002; Vargas et al, 2004). …”

Yeast activator proteins and stress response: an overview

“…The fourth member of the family, Yap4p (Cin5p/Hal6p), is a 33‐kDa protein and was initially characterized as a chromosome instability mutant [51]. Overexpression studies in the ena1 mutant subsequently identified both YAP4 ( HAL6 ) and YAP6 ( HAL7 ) as genes that confer salt tolerance through a mechanism unrelated to the Na + /Li + extrusion ATPase [12], whilst multicopy YAP4 expression was shown to confer resistance to the antimalarial drugs, chloroquine, quinine and mefloquine [9,11]. Furuchi et al [9] subsequently isolated these two genes in overexpression studies that imparted selective resistance to the chemotherapeutic agent cisplatin.…”

“…Msn2p and Msn4p bind to the stress response element (STRE), a 5-bp sequence, C4T [5]. In addition, the two basicleucine zipper (b-ZIP) transcription factors, Yap1p and Yap2p [7,8], along with six newly identified proteins, form a family of trans-regulators that have been implicated in various forms of stress response [9][10][11][12]. The large amount of data from the many laboratories that work within this field of research is reviewed in great detail elsewhere [13,14] and here, we review the main aspects of the stress response in which the yeast activator protein (Yap) factors have been shown to be involved.…”