Identification and characterization of genes whose expression is down -regulated in IFN-alpha treated Daudi cells

Jing Lou, Fordham University


A $\lambda$gt10 cDNA library prepared from polyadenylated RNA isolated from Daudi cells was differentially screened to isolate cDNAs which recognize mRNA whose levels are reduced following IFN treatment. DNA sequence analysis of twenty-five cDNA clones revealed that twenty clones represented mitochondrially-encoded mRNAs. Northern blot analysis employing these cDNAs and oligonucleotides generated to the remaining mitochondrially encoded mRNAs demonstrated that IFN-a treatment of Daudi cells mediates a time-dependent suppression of the level of the mitochondrially encoded mRNAs. Another cDNA clone isolated by differential screening encodes for the peptide chain elongation factor 1 alpha (EF-1$\alpha$), whose corresponding mRNA level is also reduced in IFN-$\alpha$ treated Daudi cells as shown by northern blot analysis. The IFN-mediated reduction in the levels of mitochondrially encoded mRNA and EF-1$\alpha$ mRNA is dependent on protein synthesis, and can be observed prior to any detectable effect of IFN-$\alpha$ on DNA synthesis. The degree of suppression of the mRNA levels correlates with the sensitivity of the cells to the anticellular action of IFN. A study of the level of cellular respiration in IFN-treated Daudi cells reveals a clear suppression in the mitochondrial electron transfer 3 h following IFN treatment. Nuclear run on assays showed that IFN-mediated reduction of EF-1$\alpha$ mRNA occurs at the level of transcription, I have also presented results suggesting that the reduction in the level of EF-1$\alpha$ mRNA following IFN treatment is mediated by promoter region upstream of the EF-1$\alpha$ gene using a CAT reporter gene system. A TGF-$\beta$1 inhibitory element (TIE) like sequence in this upstream region may be involved in the IFN-mediated reduction in the level of EF-1$\alpha$ mRNA, as shown by EMSAs.

Subject Area

Molecular biology|Cellular biology

Recommended Citation

Lou, Jing, "Identification and characterization of genes whose expression is down -regulated in IFN-alpha treated Daudi cells" (1994). ETD Collection for Fordham University. AAI9416673.