Partial rescue of GATA-3 by yeast artificial chromosome transgenes

GATA-3 is essential for murine embryonic development, but elucidating the g enetic controls over the complex temporal and tissue-specific transcription al regulatory pattern of this transcription factor gene has been problemati c. Here we report the isolation and characterization of two yeast artificia l chromosomes (YACs) bearing the murine GATA-3 gene. Ordered deletions of b oth YACs show that they define a 1-megabase pair contig spanning the GATA-3 locus. We found that a 120-kb YAC transgene, including 35 kb of 5' as well as 60 kb of 3' flanking sequence, confers normal GATA-3 expression at site s not revealed previously through analysis of plasmid transgenic lines. How ever, even this 120-kb YAC does not contain sufficient information to recap itulate the complete GATA-3 expression program during embryogenesis. While not complete in its regulatory capacity, the YAC transgene is nonetheless a ble to complement several homozygous GATA-3 mutant phenotypes and thereby p rolong embryonic life. (C) 1998 Academic Press.