A human fetal heart cDNA library was constructed in the lambda gt22A expression vector. Polymerase chain reaction (PCR) was used to amplify the cDNA inserts. PCR products were purified and used in cycle sequencing reactions in the presence of a fluorescein-conjugated primer and electrophoresed on a Pharmacia A.L.F. Sequencer. Partial cDNA sequences, or expressed sequence tags (ESTs) were searched against the Genbank and EMBL databases to identify novel genes expressed in the human cardiovascular system.