Identification of aluminium transport-related genes via genome-wide phenotypic screening of Saccharomyces cerevisiae

Abstract

Genome-wide screening using gene deletion mutants has been widely carried out with numerous toxicants including oxidants and metal ions. The focus of such studies usually centres on identifying sensitive phenotypes against a given toxicant. Here, we screened the complete collection of yeast gene deletion mutants (5047) with increasing concentrations of aluminium sulphate (0.4, 0.8, 1.6 and 3.2 mM) in order to discover aluminium (Al(3+)) tolerant phenotypes. Fifteen genes were found to be associated with Al(3+) transport because their deletion mutants exhibited Al(3+) tolerance, including lem3Δ, hal5Δ and cka2Δ. Deletion of CKA2, a catalytic subunit of tetrameric protein kinase CK2, gives rise to the most pronounced resistance to Al(3+) by showing significantly higher growth compared to the wild type. Functional analysis revealed that both molecular regulation and endocytosis are involved in Al(3+) transport for yeast. Further investigations were extended to all the four subunits of CK2 (CKA1, CKA2, CKB1 and CKB2) and the other 14 identified mutants under a spectrum of metal ions, including Al(3+), Zn(2+), Mn(2+), Fe(2+), Fe(3+), Co(3+), Ga(3+), Cd(2+), In(3+), Ni(2+) and Cu(2+), as well as hydrogen peroxide and diamide, in order to unravel cross-tolerance amongst metal ions and the effect of the oxidants. Finally, the implication of the findings in Al(3+) transport for the other species like plants and humans is discussed.

The New Role for an Old Kinase: Protein Kinase CK2 Regulates Metal Ion Transport

“…The renowned role of CK2 is its regulation of cell proliferation, including the processes of DNA replication, transcription, tRNA and rRNA synthesis, chromatin remodelling and anti-apoptosis [6,12,13]. With its high pleiotropism, it is not surprising that new aspects of CK2 functionality are continually unravelled, such as we and the others demonstrate that CK2 is involved in metal ion transport [14,15]. …”

“…It is therefore clear that under normal growth conditions the catalytic subunits are compensatory. However, several studies imply that under certain environmental conditions individual subunits confer different phenotypes [14,40,41], and, therefore, cannot be compensated by one another. In terms of the regulatory subunits, deletion of CKB1 or CKB2 or both does not lead to lethality.…”

“…Based upon the phenotype, the function of that gene can be revealed. Genome-wide screening of deletion mutants has been applied to nickel [54], cadmium [55], arsenite [56,57], lead [58], aluminium [14,59] and chromium [40]. Significantly, the findings from the yeast system are relevant to human beings due to the genomic homology between the two organisms.…”

“…By means of S . cerevisiae genome-wide deletion mutant screening, we firstly uncovered that deletion of CKA2 (CKα’) leads to resistance to Al 3+ toxicity [14]. Further, the regulatory subunits ( CKB1 and CKB2 ) were shown to be involved in regulating the toxicity of As 3+ [56].…”

Global Deletome Profile of Saccharomyces cerevisiae Exposed to the Technology-Critical Element Yttrium

“…Genomic phenotyping of knock-out (KO) mutant collections is a method of choice to decipher general functions as well as key genes involved in metal homeostasis in S. cerevisiae . This experimental approach has been widely applied, since the KO mutant collection release for various metals such as cadmium ( Ruotolo et al, 2008 ; Serero et al, 2008 ; Thorsen et al, 2009 ; Wang, L. et al, 2017 ), nickel ( Ruotolo et al, 2008 ; Arita et al, 2009 ; Bleackley et al, 2011 ), zinc ( Pagani et al, 2007 ; Wang et al, 2007 ; Jin et al, 2008 ; Bleackley et al, 2011 ), aluminum ( Kakimoto et al, 2005 ; Tun et al, 2014 ), arsenic ( Haugen et al, 2004 ; Thorsen et al, 2006 , 2009 ; Jin et al, 2008 ; Ruotolo et al, 2008 ; Serero et al, 2008 ; Johnson et al, 2016a ), copper ( Wang et al, 2007 ; Jo et al, 2008 ; Bleackley et al, 2011 ), iron ( Wang et al, 2007 ; Jo et al, 2008 ; Bleackley et al, 2011 ), manganese ( Wang et al, 2007 ; Bleackley et al, 2011 ; Chesi et al, 2012 ), cobalt ( Bleackley et al, 2011 ), or chromium ( Jin et al, 2008 ; Johnson et al, 2016b ) among others. The identified mechanisms thanks to this model organism and approach have provided insights into conserved pathways in other eukaryotes ( Botstein et al, 1997 ; Kachroo et al, 2017 ).…”