Study 3'UTR Isoforms In Vivo
Alternative polyadenylation allows gene products to escape or be part of regulative networks. This regulation seems to occur primarily in a tissue-specific rather than developmental manner. When we examined if 3'UTR isoform expression is correlated with developmental stage, we actually found that most 3'UTR isoforms of the same gene are present at the same stage, suggesting therefore that the majority of APA is tissue-specific.
We study alternative polyadenylation using transfection experiments by forcing the expression of selected "wrong" isoforms in given tissues and observe how their regulation is effected by miRNAs/RBPs. We use a single dual-reporter vector that allows to study in vivo the contribution of a given 3'UTR to post-transcriptional gene regulation output. The promoter drives equal expression of two fluorochromes connected by a trans-splicable element: the first reports the transcription level, while the second reports the translational level. Changes in the intensity of the second fluorochrome indicate post-transcriptional gene regulation triggered by a given 3'UTR. These constructs are expressed in worms using either injection or ballistic transformation. An example of the activity of the vector is shown in Figure 2.