Schematic representation of the transgenic construct. (A) The human bcl-2α cDNA was cloned in the second exon of the rat L-PK gene, maintaining the integrity of both the erythroid- (L′) and the hepatic- (L) alternative first exons of the gene. The arrow indicates the erythroid-specific transcriptional start site. (B) The transgene encodes two proteins that are translated from the indicated initiation ATG in the erythroid-specific first exon and second exon of the L-PK gene. The natural bcl-2α initiation codon was mutated by PCR. The bcl-2 signal/anchor motif, responsible for a cellular membrane location, is represented by hatched bars.