Interferon-gamma stimulation of messenger RNA for human secretory component (poly-Ig receptor) depends on continuous intermediate protein synthesis.
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.
Krajci
P
P
Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Rikshospitalet, Oslo, Norway.
Taskén
K
K
Kvale
D
D
Brandtzaeg
P
P
D003110:Colonic Neoplasms / Q000235:genetics; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects*; D012635:Secretory Component / Q000235:genetics* / Q000502:physiology; D013997:Time Factors; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects
D012333:RNA, Messenger; D012635:Secretory Component; D003609:Dactinomycin; D004004:Dichlororibofuranosylbenzimidazole; D007371:Interferon-gamma; D003513:Cycloheximide