Role in Cancer
The majority of transcripts that harbor an internal ribosome entry site (IRES) are involved in cancer development via corresponding proteins. A crucial event in tumor progression referred to as epithelial to mesenchymal transition (EMT) allows carcinoma cells to acquire invasive properties. The translational activation of the extracellular matrix component laminin B1 (LamB1) during EMT has been recently reported suggesting an IRES-mediated mechanism. In this study, the IRES activity of LamB1 was determined by independent bicistronic reporter assays. Strong evidences exclude an impact of cryptic promoter or splice sites on IRES-driven translation of LamB1. Furthermore, no other LamB1 mRNA species arising from alternative transcription start sites or polyadenylation signals were detected that account for its translational control. Mapping of the LamB1 5'-untranslated region (UTR) revealed the minimal LamB1 IRES motif between -293 and -1 upstream of the start codon. Notably, RNA affinity purification showed that the La protein interacts with the LamB1 IRES. This interaction and its regulation during EMT were confirmed by ribonucleoprotein immunoprecipitation. In addition, La was able to positively modulate LamB1 IRES translation. In summary, these data indicate that the LamB1 IRES is activated by binding to La which leads to translational upregulation during hepatocellular EMT.
Read more about this topic: Laminin
Famous quotes containing the words role in, role and/or cancer:
“Certainly parents play a crucial role in the lives of individuals who are intellectually gifted or creatively talented. But this role is not one of active instruction, of teaching children skills,... rather, it is support and encouragement parents give children and the intellectual climate that they create in the home which seem to be the critical factors.”
—David Elkind (20th century)
“What is charm then? The free giving of a grace, the spending of something given by nature in her role of spendthrift ... something extra, superfluous, unnecessary, essentially a power thrown away.”
—Doris Lessing (b. 1919)
“The truth is that Mozart, Pascal, Boolean algebra, Shakespeare, parliamentary government, baroque churches, Newton, the emancipation of women, Kant, Marx, and Balanchine ballets don’t redeem what this particular civilization has wrought upon the world. The white race is the cancer of human history.”
—Susan Sontag (b. 1933)