Figure 4.

A1 is a target of the PLCγ-Ca²⁺-NF-κB pathway. (A) A1 is a transcriptional target of NF-κB. Semiquantitative RT-PCR analysis of A1 expression in pre-TCR⁺ cell lines after the inhibition of NF-κB. In the absence of pre-TCR signaling, 50 ng/ml PMA plus 1 μg/ml Iono treatment can induce A1 expression (B), as well as NF-κB nuclear translocation and Ca²⁺ mobilization (C). (D) Ca²⁺ mobilization is essential for A1 transcriptional induction. A1 expression was examined by semiquantitative RT-PCR after chelation of intracellular Ca²⁺ by 1 mM TMB8. (E) PLCγ activation is essential for A1 induction. A1 expression levels were examined by semiquantitative and real-time RT-PCR in pre-TCR⁺ cell lines (N3T and SCB29) incubated with 10 μM of the specific PLCγ inhibitor U73122.