Fine mapping and genomic structure of ACTN2, the human gene coding for thesarcomeric isoform of alpha-actinin-2, expressed in skeletal and cardiac muscle

The present paper reports on the fine mapping of the ACTN2 gene and on the reconstruction of its genomic structure. By radiation hybrid mapping, the g ene was located about 912 cR from, the 1p-telomere, ACTN2 was placed betwee n the marker WI-9317 (alias D1S2421) and the marker AFMA045ZC5, within the chromosomal band 1q43, The gene was detected in YAC 955_c_12, This YAC was used as template DNA. for long-distance and Alu-PCR, using a set of putativ e exonic primers, designed on the cDNA sequence of alpha-actinin-2, in orde r to characterize the ACTN2 intron-exon boundaries. The entire genomic stru cture of the gene was reconstructed. The ACTN2 gene contained 21 exons, in a segment spanning about 40 kb of genomic DNA. Only the proximal part of th e gene shows a high conservation through evolution, whereas in the remainin g part a divergence from the genomic organization of C. elegans and D, mela nogaster was noticed. A series of intronic primers was specifically designe d and produced, to amplify all the exons of ACTN2, directly from genomic DN A. This will enable mutation screening in patients affected with hereditary diseases linked to the marker CA4F/R, a polymorphism in the last intron of the alpha-actinin-2 gene. (C) 1999 Academic Press.