Figure 1
Generation of tdo -deficient ( Tdo-/-) mice. (A) Schema of the Trp metabolic pathways. (a) the Kyn pathway. Over 95% of the dietary Trp is metabolized along this pathway. (b) the serotonin pathway. (c) the transamination pathway. (B) A targeting strategy for tdo gene disruption. Exons are represented as numbered boxes (coding regions; black boxes). The probe for Southern blot analysis is indicated by a solid bar. Apa I, A; Pvu II, P; Hind III, H; Eco RI, E; Xba I, X; Neo, PGK-neomycin resistant cassette; DT-A, diphtheria toxin-A. (C) Southern blot analysis of representative progeny. Tail genomic DNA was digested with Pvu II for hybridization with a specific probe against the intron sequence between exons 3 and 4 of tdo. The expected sizes of the hybridized DNA fragment for Tdo+/+ (+/+) and Tdo-/- (-/-) mice are 6.1 kb and 4.9 kb, respectively. (D) Quantitative real-time RT-PCR for tdo mRNA expression in adult liver. Mouse tdo/gapdh of adult liver in Tdo+/+ mice was arbitrarily given a value of 100%. Values are means ± S.D. (E) Western blot analysis. Total liver homogenates were immunoblotted with TDO-specific antiserum. (F) Assay for TDO enzyme activity, determined in total liver lysates from 10-week-old animals of each genotype. Values represent means ± S.D.