Figure 4.

(A) Schematic diagram of the predicted peptide sequence of DOL54. The signal peptide (SP), two somatomedin B-like repeats (Som-B), mucin-homology domain (Muc), and vitronectin-related sequences (Vtr) are indicated. (B) DOL54 immunostaining of fixed but nonpermeabilized CHO cells. The cells (Top) were stably transfected with a full length DOL54 expression plasmid, whereas the cells on the bottom are the parental strain. (C) Northern blot of RNA from human tumor samples hybridized to a DOL54 probe and tubulin loading control. The lowest gel is a human TLS-CHOP reverse transcription–PCR analysis on the same RNA. Note that the tumors positive for TLS-CHOP were also positive for DOL54. The TLS-CHOP mRNA in the positive control MEFs (lane 1) is a hybrid of murine Tls and human CHOP and is not amplified by the PCR primers used here. (D) Tumorigenicity of individual CHO clones expressing DOL54 (mice 3–6) and parental cells that do not express the protein (mice 1 and 2) injected into nude mice and photographed 10 days after injection of 10⁶ cells into each of three subcutaneous sites. The CHO clone injected into mouse no. 5 expressed ≈3-fold lower levels of DOL54 mRNA than the clones injected into mice 3, 4, and 6).