Can hTNF-α be successfully produced and secreted in filamentous fungus Aspergillus niger?

Abstract

A gene-fusion expression strategy was applied for the heterologous expression of hTNF-α in A. niger AB1.13. The TNF-α gene was fused with the A. niger glucoamylase GII form as a carrier-gene, behind its transcription control and secretion signal. The protein was expressed in the cells in the form of a glucoamylase-fusion protein, but was not present in the culture medium. From the expression of two hTNF-α analogues, LK 811 (Cys95/148) and LK 802 (Cys95/148, His107/108) respectively, we concluded that oligomerisation was not the critical point for secretion of hTNF-α in A. niger, but more probably improper folding already at the stage of monomer formation, or even incorrect processing of the molecule during the secretion pathway.