Characterization of Recombinant Plant Chromosome Fragments in Human-Arabidopsis Hybrid Cell Lines

Although plants and animals are evolutionarily distant, the structure and function of their chromosomes are largely conserved. A human-plant hybrid cell line was created previously by fusing Arabidopsis thaliana protoplasts and human HT1080 cells. This human-Arabidopsis hybrid cell line contained a neo-chromosome formed by insertion of segments of Arabidopsis chromosomes, including Arabidopsis centromere into human chromosome 15. The translocated large Arabidopsis genome fragments (~ 30 Mb) were able to maintain in the human cell background under long culture conditions. We used this unique system to investigate how the introgressed part of a plant genome was maintained in human genetic background. The analysis of the neo-chromosome in 60- and 300-day-old cell cultures by next-generation sequencing and molecular cytogenetics suggested its origin by fusion of DNA fragments of different sizes from Arabidopsis chromosomes 2, 3, 4, and 5, which were randomly intermingled rather than joined end-to-end. Although evolutionary diverged, methylation patterns in plants and animals exhibit a certain level of conservation. In this present study, we aimed to investigate the epigenetic landscape and gene expression of this large alien plant chromosomefragment in the human genome under long-term culture conditions though whole genome bisulfite sequencing. This could be a useful tool for studying the coexistence of two divergent genomes and provide insight into the fundamental principles underlying genome interactions beyond biological kingdoms.