Krajci P, Taskén K, Kvale D, Brandtzaeg P
Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Rikshospitalet, Oslo, Norway.
Scand J Immunol. 1993 Feb;37(2):251-6. doi: 10.1111/j.1365-3083.1993.tb01763.x.
Secretory component (SC or poly-Ig receptor) plays a key role in mucosal external body fluids. The aim of this study was to elucidate the molecular events underlying IFN-gamma-dependent up-regulation of SC. Using a human SC cDNA clone isolated by our laboratory, we found that IFN-gamma up-regulated SC mRNA levels in a time- and concentration-dependent manner. Moreover, in situ hybridization showed a striking increase of SC mRNA-positive HT-29 cells after IFN-gamma treatment. Inhibition with 5,6-dichloro-1-beta-ribofuranosyl-benzimidazole (DRB) indicated a half-life for IFN-gamma-induced SC mRNA of approximately 1 h. Cycloheximide (CHX) abolished the IFN-gamma-induced accumulation of SC mRNA in a reversible manner; the time-course suggested that de novo synthesis of protein factor(s) with a turnover time shorter than 6 h was required for accumulation of SC message. IFN-gamma-stimulated up-regulation of SC expression therefore appears to depend on molecular events similar to those taking place for the activation of several other genes in the Ig supergene family.
分泌成分（SC或多聚免疫球蛋白受体）在黏膜外体液中起关键作用。本研究的目的是阐明IFN-γ依赖性上调SC的分子机制。利用我们实验室分离的人SC cDNA克隆，我们发现IFN-γ以时间和浓度依赖性方式上调SC mRNA水平。此外，原位杂交显示IFN-γ处理后SC mRNA阳性的HT-29细胞显著增加。用5,6-二氯-1-β-D-呋喃核糖基苯并咪唑（DRB）抑制表明IFN-γ诱导的SC mRNA半衰期约为1小时。环己酰亚胺（CHX）以可逆方式消除了IFN-γ诱导的SC mRNA积累；时间进程表明，SC信息积累需要从头合成周转时间短于6小时的蛋白质因子。因此，IFN-γ刺激的SC表达上调似乎依赖于与Ig超基因家族中其他几个基因激活所发生的分子事件相似的分子事件。
