Identification of H2A and H2B residues required for growth in the absence of <i>RKR1</i>.

<p><b>(A)</b> Synthetic lethal/sick phenotypes of <i>rkr1∆ hta1</i> and <i>rkr1∆ htb1</i> mutants were assessed through ten-fold serial dilution assays. Double mutant cells, as well as control <i>RKR1 hta1</i> and <i>RKR1 htb1</i> cells, were plated on SC-His medium as a growth control and on SC-His + 5-FOA medium to select for histone mutant plasmids and against the <i>URA3</i>-marked <i>HTA1-HTB1</i> plasmid. Library plasmids were transformed into the <i>rkr1∆</i> strain KY981 and wild-type strain KY943. KY2265 and KY2249 were used as respective negative and positive growth controls on 5-FOA plates. (<b>B)</b> X-ray crystal structure of the nucleosome, denoting histones H2A, H2B, H3, and H4 in cyan, green, yellow, and white, respectively. As depicted in red, the majority of histone residues identified in the <i>rkr1∆</i> synthetic lethality screen form a surface-exposed patch on the nucleosome. <b>(C)</b> Electrostatic potential (red is negative, blue is positive) of the nucleosome core particle. This figure was created using Pymol (PDB 1ID3 [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005420#pgen.1005420.ref035" target="_blank">35</a>]).