Genomic organization, alternative polyadenylation, and chromosomal localization of Grg, a mouse gene related to the groucho transcript of the Drosophila Enhancer of split complex.

The Grg gene encodes a 197-amino-acid protein homologous to the amino-terminal domain of the product of the groucho gene of the Drosophila Enhancer of split complex. We describe here the genomic organization of the mouse Grg gene. It spans approximately 7 kb on chromosome 10 and consists of seven exons. The 3' region of the Grg gene contains two functional polyadenylation sites that give rise to two transcripts that are differentially expressed among adult mouse tissues. The promoter region is very GC rich and lacks TATA box and "initiator" sequences. Primer extension analysis and ribonuclease protection assays show that Grg has a major transcription start site situated down-stream of putative binding motifs for the transcription factors Sp1, E2A, and PuF.