Inventory of high-abundance mRNAs in skeletal muscle of normal men

The serial analysis of gene expression (SAGE) method was used to generate a catalog of 53,875 short (14 base) expressed sequence tags from polyadenyla ted RNA obtained From vastus lateralis muscle of healthy young men. Over 12 ,000 unique tags were detected. The frequency of occurrence of each tag ref lects the relative abundance of the corresponding mRNA. The mRNA species th at were detected 10 or more times, each comprising greater than or equal to 0.02% of the mRNA population, accounted for 64% of the mRNA mass but <10% of the total number of mRNA species detected. Almost all of the abundant ta gs matched mRNA or EST sequences cataloged in GenBank. Mitochondrial transc ripts accounted for similar to 20% of the polyadenylated RNA. Transcripts e ncoding proteins of the myofibrils were the most abundant nuclear-encoded m RNAs. Transcripts encoding ribosomal proteins, and those encoding proteins involved in energy metabolism, also were very abundant. The database can be used as a reference for investigations of alterations in gene expression a ssociated with conditions that influence muscle function, such as muscular dystrophies, aging, and exercise.