MAPPING OF THE MOUSE ACTIN CAPPING PROTEIN ALPHA-SUBUNIT GENES AND PSEUDOGENES

Capping protein (CP), a heterodimer of alpha and beta subunits, is fou nd in all eukaryotes. CP binds to the barbed ends of actin filaments i n vitro and controls actin assembly and cell motility in vivo. Vertebr ates have three alpha isoforms (alpha 1, alpha 2, alpha 3) produced fr om different genes, whereas lower organisms have only one gene and one isoform. We isolated genomic clones corresponding to the alpha subuni ts of mouse CP and found three alpha 1 genes, two of which are pseudog enes, and a single gene for both alpha 2 and alpha 3. Their chromosoma l locations were identified by interspecies backcross mapping. The alp ha 1 gene (Cappa1) mapped to Chromosome 3 between D3Mit11 and D3Mit13. The alpha 1 pseudogenes (Cappa1-ps1 and Cappa2-ps2) mapped to Chromos omes 1 and 9, respectively. The alpha 2 gene (Cappa2) mapped to Chromo some 6 near Ptn. The alpha 3 gene (Cappa3) also mapped to Chromosome 6 , approximately 68 cM distal from Cappa2 near Kras2. One mouse mutatio n, de, maps in the vicinity of the alpha 1 gene. No known mouse mutati ons map to regions near the alpha 2 Or alpha 3 genes. (C) 1997 Academi c Press.