MOLECULAR ANALYSIS OF A GLUCOSE-REGULATED GENE (GRP78) OF NEUROSPORA-CRASSA

The nucleotide sequence of the gene encoding the glucose-regulated pro tein 78 (GRP78) of Neurospora crassa was determined. The ORF codes for a protein of 662 amino acids (72 kDa) and belongs to the heat shock p rotein 70 (hsp70) gene family, which is characterized by three HSP70 ' signature sequences'. The grp78 gene contains 5 introns. The protein c arries the ER retention signal HDEL at its carboxy terminus and is mos t homologous to the KAR2/GRP78 protein of Saccharomyces cerevisiae (78 %) and to KAR2/BiP of Yarrowia lipolytica (76%). The expression of grp 78 is constitutive and can be enhanced by starvation, treatment with t unicamycin, the calcium ionophore A23187 or elevated temperatures (40 degrees C). An uninterrupted ORF was found on the reverse cDNA strand of grp78. The putative peptide shows 47% homology to the NAD-specific glutamate dehydrogenase of Achlya klebsiana. (C) 1998 Elsevier Science B.V.