Pumpkin hydroxypyruvate reductases with and without a putative C-terminal signal for targeting to microbodies may be produced by alternative splicing

Two full-length cDNAs encoding hydroxypyruvate reductase were isolated from a cDNA library constructed with poly(A)(+) RNA from pumpkin green cotyledons. One of the cDNAs, designated HPR1, encodes a polypeptide of 386 amino acids, while the other cDNA, HPR2 encodes a polypeptide of 381 amino acids. Although the nucleotide and deduced amino acid sequences of these cDNAs are almost identical, the deduced HPR1 protein contains Ser-Lys-Leu at its carboxy-terminal end, which is known as a microbody-targeting signal, while the deduced HPR2 protein does not. Analysis of genomic DNA strongly suggests that HPR1 and HPR2 are produced by alternative splicing.