Abstract: The invention provides methods and compositions for expressing targeted gene products in vertebrate neurons. The compositions include gene trap vectors comprising a polynucleotide comprising promoterless selectable marker and axon reporter encoding sequences, which may be operatively joined to an internal ribosome-entry site, and may comprise a splice acceptor site located 5′ to the selectable marker and axon reporter encoding sequences. The methods include methods of expressing an axon reporter in a cell by transferring the subject vectors into an embryonic stem cell and incubating the cell under conditions whereby the cell or a progeny of the cell differentiates into a neuron comprising an axon or dendrites, and the neuron expresses the axon reporter under the transcriptional control of the gene; and specifically detecting the axon reporter in the axon or dendrites. Neuronal specific expression may also be effected in disclosed binary systems.

Abstract: The invention relates to secretory gene trap vectors and methods of using such vectors to isolate extracellular proteins and to make cells and organisms with mutant secretory genes. The vectors encode a type II transmembrane domain and a secretory lumen -sensitive indicator marker and optionally, a selectable marker and an exon-splice acceptor site. The gene isolation methods involve stably introducing the secretory trap vectors into an endogenous gene whereby the expression of the resultant fusion protein provides a differential expression of the indicator marker depending on whether the endogenous gene provides an N-terminal signal sequence.

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.