SORORIN is an evolutionary conserved antagonist of WAPL

Abstract

AbstractCohesin mediates sister chromatid cohesion to enable chromosome segregation and DNA damage repair. To perform these functions, cohesin needs to be protected from WAPL, which otherwise releases cohesin from DNA. It has been proposed that cohesin is protected from WAPL by SORORIN. However,in vivoevidence for this antagonism is missing and SORORIN is only known to exist in vertebrates and insects. It is therefore unknown how important and widespread SORORIN’s functions are. Here we report the identification of SORORIN orthologs inSchizosaccharomyces pombe(Sor1) andArabidopsis thaliana(AtSORORIN).sor1Δmutants display cohesion defects, which are partially alleviated bywpl1Δ. Atsororinmutant plants display dwarfism, tissue specific cohesion defects and chromosome mis-segregation. Furthermore,Atsororinmutant plants are sterile and separate sister chromatids prematurely at anaphase I. The somatic, but not the meiotic deficiencies can be alleviated by loss of WAPL. These results providein vivoevidence for SORORIN antagonizing WAPL, reveal that SORORIN is present in organisms beyond the animal kingdom and indicate that it has acquired tissue specific functions in plants.