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 gree n 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 seq uences of these cDNAs are almost identical, the deduced HPR1 protein c ontains Ser-Lys-Leu at its carboxy-terminal end, which is known as a m icrobody-targeting signal, while the deduced HPR2 protein does not. An alysis of genomic DNA strongly suggests that HPR1 and HPR2 are produce d by alternative splicing.