CLONING AND SEQUENCING A NOVEL METALLOTHIONEIN-I ISOFORM EXPRESSED INHUMAN RETICULOCYTES

Total RNA from human reticulocytes mas purified and reverse-transcribe d into cDNA using an oligo-dT primer, This cDNA was used as a template for a polymerase chain reaction (PCR) with a primer specific for the N-terminal sequence of mammalian metallothioneins (MT) and a universal primer, A single amplified fragment was thus generated which when clo ned and sequenced revealed two distinct MT cDNAs of almost identical m olecular weights. One sequence was identical to that previously report ed for human MT II and the other encoded a novel MT I isoform (MT I-R) The DNA sequence of MT 1(R) is distinct from those documented for oth er MT I isoforms.