Quantification of endogenous and Tg Foxn1 expression by quantitative RT-PCR. (A) RT-PCR shows specificity of primers that detect both the endogenous and transgene Foxn1 and primers that only detect transgene Foxn1 transcripts. Each lane represents results from a WT or Foxn1Tg mouse (line 60). (B) Diagram showing the relative positions of the forward and reverse primers that detect either both endogenous and transgene (arrows) or only Tg (arrow outlines) Foxn1 transcripts. (C) Expression of the endogenous and transgene Foxn1 in 2-month-old (n = 3) and 23- to 28-month-old (n = 3) Tg line (line 60). The numbers of transcripts per microgram of total RNA were calculated from a standard curve after normalization with the mouse housekeeping gene Gapdh; each sample was performed in triplicates. The endogenous Foxn1 levels were determined by subtracting the total Foxn1 (endogenous plus transgene) from that of the transgene. White bars represent the total Foxn1 levels; gray bars, Tg Foxn1; and black bars, endogenous Foxn1. Errors bars represent SD. (D) Expression of total Foxn1 in WT (n = 2 at 2 months; n = 3 at 24 months) and in the 2 Foxn1Tg lines (line 60: n = 3 at 2 months and n = 3 at 24 months; line 5: n = 4 at 25-35 months). WT: white bar represents 2 months of age; and gray bar, 24 months of age. Foxn1 Tg: white bar represents 2 months of age; gray bar, 24 months of age (line 60); crossed bars represent 25 to 35 months of age (line 5). y-axis is in logarithmic scale. Errors bars represent SD.