Developmental profile of kainate receptor subunit KA1 revealed by Cre expression in YAC transgenic mice

To determine the spatio-temporal expression in brain of the high-affinity k ainate receptor subunit KA1, we generated transgenic mice expressing Cre re combinase from the KA1 gene on a chromosomally integrated 550 kb yeast arti ficial chromosome (YAC). Activity of the KA1 gene promoter during brain dev elopment was visualized by Cre immunohistochemistry, and by X-gal staining of P-galactosidase induced by Cre recombinase in double transgenic KA1-Cre/ lacZ indicator mice. During early brain development, expression from the YA C-carried KA1-Cre transgene was observed in all major brain areas, predicti ng a function for KA1 in the developing central nervous system. In the adul t brain, KA1-Cre transgene expression was restricted mainly to hippocampal CA3 pyramidal and dentate gyms granule cells, an adult expression pattern c haracteristic for the endogenous KA1 alleles. KA1-Cre transgenic mice may h elp in elucidating the role of flexed genes ablated in vivo in KA1 expressi ng neurons. (C) 2000 Elsevier Science B.V. All rights reserved.