Fig. 6
RIP in Trichoderma reesei. a Schematic diagram of the gene deletion cassettes in the three mutants. Each cassette consists of three components: the dominant hygromycin B-resistant marker open reading frame (hph; green box), flanked by an upstream promoter (Ppki or PtrpC), and/or a downstream terminator (Tcbh2). The full-length hph gene has 1026 bps. A truncated hph-ΔN 304-1026-Tcbh2 cassette was spontaneously generated in blr1Δ during transformation. The dark line underneath hph represents the DNA probe used for Southern hybridization. The upstream and downstream neighboring genes of the deleted gene are indicated by white boxes and their protein identity numbers. In blr1Δ, there are two identical 12960 fragments (in yellow) and two copies of Tcbh2 (in white). b Southern hybridization. Genomic DNA of indicated strains was digested by SalI or Sfo1, and then subjected to Southern blot analysis using the hph DNA probe shown in a. c Occurrence of RIP in the F1 progeny. The C-to-T point mutations in the respective full-length hph cassettes (in green) are indicted by vertical black bars. Only the results of one representative sexual crossing experiment (n = 10) are shown. The full-length hph cassette in each progeny was amplified by polymerase chain reaction (PCR) and then sequenced by Sanger’s method