CHARACTERIZATION OF THE BIP GENE OF ASPERGILLUS-AWAMORI ENCODING A PROTEIN WITH AN HDEL RETENTION SIGNAL HOMOLOGOUS TO THE MAMMALIAN BIP INVOLVED IN POLYPEPTIDE SECRETION
Mj. Hijarrubia et al., CHARACTERIZATION OF THE BIP GENE OF ASPERGILLUS-AWAMORI ENCODING A PROTEIN WITH AN HDEL RETENTION SIGNAL HOMOLOGOUS TO THE MAMMALIAN BIP INVOLVED IN POLYPEPTIDE SECRETION, Current genetics, 32(2), 1997, pp. 139-146
A DNA fragment containing an open reading frame of 2016 nucleotides ha
s been cloned from the DNA of Aspergillus awamori by hybridization wit
h a probe internal to the KAR2 (BiP) gene of Saccharomyces cerevisiae.
The 73.4-kDa-encoded protein showed very high similarity to the endop
lasmic reticulum (ER) lumenal BiP protein of S. cerevisiae, Kluyveromy
ces lactis, Schizosaccharomyces pombe, and animal and plant cells. The
BiP protein contains a polar N-terminal end followed by a 18-amino-ac
id strongly hydrophobic region corresponding to the leader peptide for
transport through the ER membrane. In the C-terminal region the prote
in ends with the HDEL canonical ER retention signal that targets prote
ins to the lumen of the ER. The A. awamori bip gene contains three int
rons as shown by cloning and sequencing the putative intron regions fr
om a cDNA library. The bip gene is transcribed as a monocistronic mRNA
of 2.4 kb. Two transcription start sites located 160 and 233 bp upstr
eam of the first translated ATG were identified by primer extension. T
he promoter region showed no consensus TATA box but it contains CCAAT
and CreA boxes known to be involved in both stress and carbon-cataboli
te regulation of fungal promoters.