RAT DESMIN GENE STRUCTURE AND EXPRESSION

The isolation of two partial genomic clones and a near full length cDNA clone encoding the rat intermediate filament protein desmin is reported. Desmin is a differentiation marker for all types of muscle cells. The nucleotide order of the coding region and 0.1 kb of 5'-flanking sequences of the rat desmin gene has been determined. One genomic clone encompasses exons I-III and approx. 12 kb of 5'-flanking sequences, while the other clone contains exons VII-IX and about 12 kb of 3'-flanking sequences. Northern analysis of RNA from different organs reveals that, as expected, desmin is expressed in striated, heart and smooth muscle cells containing tissues; among other tissues, lung displays relatively high expression levels, while desmin mRNA is barely detectable in spleen, kidney and liver. S1 mapping reveals that the same transcription initiation site is used in all desmin mRNA containing tissues.