| abstract |
A yeast expression cloning vector comprising the following sequence 5'-SP-Xn-3'-RS-5'-Xm-(NZT)p-Xq-PS-*gene*-3' wherein SP is a DNA sequence encoding a signal peptide, Xn is a DNA sequence encoding n amino acids, wherein n is 0 or an integer of from 1 to about 10 amino acids, RS is a restriction endonuclease recognition site provided at the junction of Xn and Xm, Xm is a DNA sequence encoding m amino acids, wherein m is 0 or an integer from 1 to about 10, (NZT)p is a DNA sequence encoding Asn-Xaa-Thr, wherein p is 0 or 1, Xq is a DNA sequence encoding q amino acids, wherein q is 0 or an integer from 1 to about 10, PS is a DNA sequence encoding a peptide defining a yeast processing site, and *gene* is a DNA sequence encoding a heterologous polypeptide. The vector may be used to construct synthetic leader peptide sequences by inserting random DNA fragments in the "RS" site, culturing a yeast cell transformed with this vector and screening the culture for secretion of the heterologous polypeptide. |