HUMAN REPEAT-MEDIATED INTEGRATION OF SELECTABLE MARKERS INTO SOMATIC-CELL HYBRIDS

We describe a strategy to introduce preferentially the dominant select able marker neo(R) into the human chromosome within a monochromosome h ybrid cell line. Integration of a construct containing the marker is m ediated by human-specific repeat elements that promote multilocus huma n-specific integration with a single targeting vector. We tested two c lasses of repeat elements: the Alu family of SINE repeats and the Line l repeat family. We show that Alu sequences alone are insufficient to direct human-specific integration but when used in combination with a Linel element, or when only Linel elements are included, integration o f the vector into the human component of a monochromosome somatic cell hybrid is Favored. The vectors also carry sequences that facilitate m apping and selective cloning of the targeted region. This strategy pro vides a means to generate selectable human subchromosomal fragments th at can be used for localization of genes through positional cloning an d, more important, for the identification of functional units through DNA transfer.