Global effect of JTV or JTV-Alt overexpression in HeLa cells

JTV is not only a structural component of multi-aminoacyl-tRNA synthetase complex, but also a regulator of FBP that in turn controls c-Myc expression. In order to identify JTV target genes other than FBP and c-Myc, JTV or JTV-Alt (alternatively spliced form of JTV, enriched in the nucleus) protein was over-expressed in HeLa cells and global gene expression changes were monitored using cDNA expression microarray. JTV or JTV-Alt was expressed in HeLa cells by transient transfection as protein fusion with GFP. After harvesting, only GFP-positive cells were isolated by flow cytometry, and used for RNA extraction. Each JTV or JTV-Alt sample was analyzed by co-hybridizing with control GFP-only samples. Each of the two forms of JTV hybridization was repeated as biological replicate.