Mutational analysis of the SOCS-1 gene. (A) Gel view of a DNA 1000 LabChip biosizing assay. SOCS-1 mRNA–specific PCR products from RT-PCR assays on RNA derived from MedB-1 cells (lane 1) and autologous fibroblasts (lane 2). Lanes 3, 4, and 5 represent specific SOCS-1 gene fragments amplified by PCR on DNA separated from MedB-1 cells (lane 3), autologous fibroblasts (lane 4), and tumor tissue (lane 5). Wild-type SOCS-1 sequence appeared as the 201-bp band. St, standard 200 bp and 150 bp, respectively. (B) Detailed sequencing chromatogram of the 193-bp PCR product indicates an 8-bp deletion (red sequence) causing a reading frame shift (altered protein sequence is given in italics). (C) Detailed sequencing chromatogram of the 177 bp PCR product indicating an inframe deletion of 24 nucleotides (red sequence) and loss of 7 amino acids. DNA and protein sequences are numbered relative to the start as 1.