Genomic organization of a mouse type I activin receptor

We have characterized the genomic organization of a mouse type I activin receptor. Using the mouse tsk7L cDNA, 4 overlapping lambda clones containing the activin receptor IA (ActRIA) gene were isolated from a mouse 129 Sv genomic library. The mouse ActRIA gene is encoded by 10 exons and spans approximately 40 kb. The size of the introns was determined and the intron/exon boundaries were sequenced. Primer extension analysis of the 5' non-translated region using RNA from different organs or tissues revealed a strong transcription start site 68 nucleotides upstream of the ATG. Knowledge of the structure of the ActRIA gene is essential for the production of ActRIA deficient mice by homologous recombination.