FIGURE 3.

WRN multimerization domain forms highly stable multimers and contains a coiled coil motif. A, multiple sequence alignment of Homo sapiens WRN amino acids 247–299 with Pan troglodyte, Equus caballus, Canis familiaris, Bos taurus, Mus musculus, Rattus norvegicus, Monodelphis domestica, Ornithorhynchus anatinus, Gallus gallus, Xenopus laevis, Xenopus tropicalis, and Taeniopygia guttata WRN homologues reveals a conserved heptad repeat coiled coil motif. Heptad positions 1 and 4 are highlighted in blue and green, respectively; protein species names and start and end amino acids are denoted. Asterisks denote a conserved break in the heptad pattern of WRN proteins. Human RecQ1 coiled coil is shown for comparison (bottom). B, SDS-PAGE of recombinant His₆-WRN(221–333) nickel resin pull-down experiments; extract (Input), nickel bead supernatant (Sup.) and nickel resin eluate (Eluate) are indicated. C, Western blot of the same experiment using rabbit polyclonal antibodies recognizing the epitope(s) within WRN(236–333). D, Western blot of repeated experiment, including E. coli control lane probed with antibodies recognizing polyhistidine.