The Nab2 and Stat6 genes share a common transcription termination region

The two Nab genes, coding for transcriptional corepressors of NGFI-A (Egr-1, Krox24, zif268) and Krox20, have been localized to two regions of the genome, each of which contains at least two members of the Stat gene family. The association of the two Nab genes with the Stat clusters on mouse chromosomes 1 and 10 (human chromosomes 2 and 12) suggest that a Nab gene was involved in at least one of the duplication events that resulted in dispersion of the primordial Stat gene pair to three different mouse chromosomes. Sequencing of the Nab2 genomic locus revealed that it is situated very close to the Stat6 gene. The transcripts of the two genes converge, such that the 3' ends of the Stat6 and Nab2 mRNAs overlap by 58 bp. Both transcripts terminate within a 78-bp region that is absolutely conserved between mouse and human. Analysis of Nab2 cDNA revealed that there is an alternatively spliced form of the Nab2 transcript (lacking exon 3) that produces a protein that lacks the ability to repress transcription by NGFI-A and Krox20.