Similarly, GFP can be used as an indicator of protein expression in heterologous systems. Insertion of the gene in the heterologous host is performed by recombinant DNA technology. These types of media significantly increase the cost of producing heterologous proteins. "P. pastoris" is frequently used as an expression system for the production of heterologous proteins. A can also down-regulate TP in a process termed heterologous desensitization. It is unknown whether the EsV-1 protein can form a functional channel in heterologous cells. "Nde"I is useful in generating heterologous DNA construct because it contains the start codon ATG. In recent years, biotechnology researchers have begun using "Streptomyces" species for heterologous expression of proteins. This feature is compatible with heterologous protein expression, giving higher yields of production. The heterologous protein is inserted at the passenger domain. Scaffolds are used to display the heterologous protein on the bacterial cell surface. Production of heterologous proteins by fed-batch cultures of recombinant microorganisms have been extensively studied. Heterologous expression can be done in many type of host organisms. Certain strains of "S. coelicolor" can be used for heterologous protein expression. Some vaccines have heterologous effects, also called non-specific effects.