Figure 4

GRB2 regulates miRNA expression in HEK293T cells. (a) Western blot of GRB2 expression in wild type (293 T) and depleted (G1) HEK293T clones 1 (G1.1) and 2 (G1.2). While G1.1 is a complete knockout, G1.2 contains a deletion and large insertion in the N-terminal SH3 domain. GRB2 was blotted with an antibody which recognised the C-terminal SH3 domain. Both long and short exposures were used to capture the GRB2 bands, whereas the GAPDH image was captured using a short exposure only. All images are taken from the same western blot. N = 3. (b) Heat plot highlighting miRNAs which show significant log2(fold changes) in expression (p < 0.05) between wild type HEK293T and G1 cells, measured by small RNA sequencing. Cells were deprived of growth factor. miRNAs demonstrated positive (red) and negative (blue) expression changes. N = 2. (c, d) RT-qPCR analysis of fold-change in mean expression of precursor miRNA transcripts (precursor and primary, pre-mir-, hashed bars) and mature miRNA (miR-, plain bars) derived from serum-starved G1 or wild type HEK293T cells. Two groups of miRNAs were observed: (c) miRNAs which diminished at both the level of the precursor and mature transcripts and, (d) miRNAs which were enhanced as mature transcripts but not as precursors. Comparisons were made using a two-tailed Student’s t-test and error bars show standard error of mean. N = 4. ns = not significant.