Identification of Genes Associated with Myocardial Development

We are conducting a cDNA sequencing project using human heart cDNA libraries to study expression of genes in the human heart. From our human heart cDNA libraries, we have accumulated over 10 000 partial cDNA sequences (expressed sequence tags—ESTs) representing both the previously uncharacterized and known transcripts expressed in the human heart (Liewet al., 1994). Currently, we have applied dot blot hybridization as a rapid approach to determine the genes putatively involved in myocardial development. Differential expression patterns of gene transcripts represented by the cDNA clones can be revealed by comparing dot intensities on the autoradiographs, after hybridization with cDNA probes generated from neonatal and adult heart mRNAs. cDNA clones (1505) have been processed by dot blot hybridization, of which 924 and 581 represented novel and known transcripts respectively. Among the screened clones, about 1.4% were found to be differentially expressed during heart development. Further verification was accomplished by Northern blot analysis. By grouping the 581 clones corresponding to known transcripts, a study of the gene expression profile of the heart in the cardiovascular system can be achieved.