tokens: During the cloning by reverse transcriptase-polymerase chain reaction of the human HIF-1alpha subunit , we isolated two cDNA clones which corresponded to alternative splicing of the HIF-1alpha gene .
folded_tokens: during the cloning by reverse transcriptase-polymerase chain reaction of the human hif-1alpha subunit , we isolate two cdna clone which correspond to alternative splicing of the hif-1alpha gene .