Abstract: Novel vectors are provided for capturing target genes, especially genes encoding membrane and secreted proteins as well as recombinant DNA molecules comprising sequences encoding genes so captured as well as the expression products of such genes.The vectors comprise a component which upon insertion into a target eukaryotic gene produces a modified gene which on expression codes for a polypeptide having a portion of its amino acid sequence encoded by a nucleic acid sequence of the target eukaryotic gene and a portion of its amino acid sequence encoded by a nucleic acid sequence of the vector. The vector includes a sequence which confers on the polypeptide a property which is differentially associated with the presence in the target eukaryotic gene of a nucleic acid sequence coding for an amino acid sequence which results in the product of expressing the target eukaryotic gene being located in a predetermined spatial relationship with structural components of the host cell, e.