Long non-coding RNA INXS is a critical mediator of BCL-XS induced apoptosis.
Bottom Line: These effects were abrogated in the presence of INXS knockdown.Similarly, ectopic INXS overexpression caused a shift in splicing toward BCL-XS and activation of caspases, thus leading to apoptosis.BCL-XS protein accumulation was detected upon INXS overexpression.
Affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-900 São Paulo, SP, Brasil.Show MeSH
Related in: MedlinePlus
Mentions: To test the effect of INXS ectopic overexpression on BCL-X alternative splicing, 786-O cells were transiently transfected with increasing concentrations of a pCEP4-INXS vector; after 24 h, the transfected 786-O cells showed a 15- to 40-fold increase in INXS compared with the endogenous INXS lncRNA expression level in untransfected cells (Figure 6A, blue bars). The mRNA abundance of the BCL-XL isoform was reduced up to 4-fold in 786-O cells transfected with 3 μg of plasmid compared with wild-type cells (Figure 6A, red bars). Interestingly, BCL-XS mRNA expression showed a 20-fold increase relative to that of wild-type (Figure 6A, black bars). It is noteworthy that the relative abundance ratio of BCL-XS/BCL-XL was markedly increased, up to ∼60-fold (Figure 6B), from 0.06 in untransfected cells to 3.3 in cells with the highest level of INXS lncRNA overexpression; no change in the total BCL-X mRNA (Figure 6C) was observed. At the highest INXS lncRNA levels, the pro-apoptotic BCL-XS isoform was clearly predominant (∼80% of all BCL-X mRNA in the cell).
Affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-900 São Paulo, SP, Brasil.