Question

6. Cells have proteins that form silencing complexes, blocking transcription or translation of genes. In order to target specific genes, the silencing complexes associate with a guide molecule.

a. What guide molecules enable silencing complexes to specifically target transposable elements? b. W

hat is the genetic source of these guide molecules?

Answer 1

a. siRNA molecules act as guide molecules for silencing complexes. siRNA molecules are short RNA fragments which direct silencing complexes to associate with a particular genome sequence resulting in repression of transcription or translation of that particular gene.

b. Source of siRNA molecules: siRNAs are short (generally 20-24bp), double stranded RNA fraggments with phosphorylated 5' ends and hydroxylated 3' ends with two overhanging nucleotides. These siRNAs are produced from long dsRNA or small hairpin RNA with the help of an enzyme known as dicer. siRNA are also synthetically produced by using biotechnological tool.