THE STRUCTURAL ORGANIZATION OF LAMA4, THE GENE ENCODING LAMININ ALPHA-4

We have determined the complete structural arrangement of LAMA4, the g ene encoding the laminin alpha 4 chain. Using both yeast artificial ch romosome clones and total human genomic DNA and primers derived from t he cDNA sequence, regions of the gene were amplified and sequenced to determine the splice donor and acceptor sites. The introns were sized by agarose gel electrophoresis of the PCR products. The gene consisted of 39 exons spanning 122 kb. All of the splice sites conformed to the GT/AG rule, except intron 7 which possessed a GC dinucleotide at the donor splice site. The intron/exon ratio was large at 17.8:1, mainly d ue to large introns at the 5' end of the gene. Regions at both the 5' and 3' end of the gene were subcloned from the yeast artificial chromo somes to enable untranscribed DNA to be sequenced. The gene represents the second of the laminin A gene family to be characterised and its s tructural organisation is similar to the equivalent regions of the LAM A2 gene.