Restricted expression of LUZP in neural lineage cells: A study in embryonic stem cells

A novel protein LUZP with 3 leucine zipper motifs at its amino terminus is predominantly expressed in the adult brain. A modified gene targeting appro ach was employed in an attempt to establish in vitro and in vivo models in which Luzp is knock-out (KO) for phenotype assessment and a reporter gene l acZ is knock-in (KI) for tracing its expression. We report in this study th e molecular cloning of the Luzp gene, its targeting vector construction and Luzp-KO/IacZ-KI embryonic stem (ES) clone selection. Since LUZP is also ex pressed in ES cells, the possibility of embryonic lethality cannot be exclu ded when attempting to establish Luzp-null mutant mice. We have therefore e xamined the development of homozygous Luzp-KO/lacZ-KI clones in nude mice. Tissue types derived from all three embryonic germ layers were observed in teratomas developed in nude mice. In situ X-gal staining further revealed r estricted expression of LUZP in neural lineage cells. Copyright (C) 2001 Na tional Science Council, ROC and S. Karger AG, Basel.