NOVEL GENE TRANSCRIPTS PREFERENTIALLY EXPRESSED IN HUMAN MUSCLES REVEALED BY QUANTITATIVE HYBRIDIZATION OF A HIGH-DENSITY CDNA ARRAY

A set of 1091 human skeletal muscle cDNA clone inserts representing mo re than 800 human gene transcripts were spotted as PCR products at hig h density on nylon membranes. Replicas of the filters were hybridized in stringent conditions with P-33-radiolabeled cDNA probes transcribed from skeletal muscle poly(A)(+) RNA. Hybridization signals were colle cted on phosphor screens and processed using a software specifically a dapted for this application to identify and quantitate each spot. Para meters likely to influence the hybridization signal intensity were ass essed to eliminate artifacts. Each clone was assigned to one of four i ntensity classes reflecting the steady-stare level of transcription of the corresponding gene in skeletal muscle. Differential expression of specific gene transcripts was detected using complex cDNA probes deri ved from nine different tissues, allowing assessment of their tissue s pecificity. This made it possible to identify 48 novel gene transcript s (including 7 homologous or related to known sequences) with a muscle -restricted pattern of expression. These results were validated throug h the analysis of known muscle-specific transcripts and by Northern an alysis of a subset of the novel gene transcripts. All these genes have been registered in the Genexpress Index, such that sequence, map, and expression data can be used to decipher their role in the physiology and pathology of human muscles.