Abstract: A gene trap vector comprises a DNA construct containing an expression unit of an internal ribosome binding site (IRES) coupled to a heterologous gene sequence; this expression unit is used in gene trap protocols to obtain expression of the heterologous gene in the host.

Abstract: A method is provided for treating a patient in need of therapy for acute neuronal degeneration due to metabolic compromise of central or peripheral nervous system cells comprising administering to that patient a therapeutically effective amount of a 7&agr;-hydroxy substituted steroid selected from 7&agr;-hydroxy-derivatives of estradiols, dehydroepiandrosterones and pregnenolones, and metabolic precursors thereof. Use of such compounds for manufacture of medicaments and neuroprotective compositions are also provided.

Abstract: This invention relates to DNA constructs for inserting heterologous gene sequences into a host genome so as to obtain expression of the heterologous gene, to methods of inserting heterologous gene sequences into a host genome, and to organisms carrying modified host genomes. Specifically, the DNA constructs of this invention contain an expression unit of an internal ribosome binding site (IRES) coupled to a heterologous gene sequence. This expression unit is flanked at the 5' and 3' ends by DNA sequences that enable homologous recombination or integration of the construct with the DNA of a targeted host to obtain expression of the heterologous gene in the host.