Fig. 1.

The familial segregation and expression pattern of the ISG15 allele indicates recessive inheritance and an absence of protein production. Familial segregation in a family from Turkey (Kindred A) and a family from Iran (Kindred B) (A). Graphical representation of the proISG15 protein. The LRLRGG ISGylation domain, the 8-amino acid sequence (black) cleaved to yield active ISG15, and the putative proteins synthesized in the patients (B) are shown. EBV-B cells from Control 1 (C1), Control 2 (C2), a STAT1^−/− patient (negative control) and patient 1 (P1), were left untreated or treated with IFN-α. The cells were then lysed and the lysates were subjected to western blotting (C). EBV-B cells from Control 1 (C1), a STAT1^−/− patient and patient 1 (P1) were stained with ISG15 and STAT1 antibodies and analyzed by flow cytometry (D). SV-40-fibroblasts from Control 1 (C1), a STAT1^−/− patient, P1, and P2 were analyzed as in C (E). All experiments presented were performed at least 3 times.