Fig. 1.

Targeted gene knockout of Trste20 and promoter substitution of Trsho1, Trsln1 or Trypd1. a Schematic illustration of the homologous integration of the tcu1 promoter in front of the Trsho1, Trsln1 or Trypd1 gene locus. A promoter substitution cassette harboring the tcu1 promoter and a pyr4 marker was integrated into the Trsho1, Trsln1 or Trypd1 locus by homologous recombination. b Schematic representation of Trste20 deletion. Trste20 was replaced by the pyr4 gene via homologous recombination