Insulin receptor alternative splicing and insulin signalling in <i>biceps brachii</i> and <i>tibialis anterior</i> muscles of DM1 patients.

<p><b>(A)</b><i>INSR</i> splicing products obtained by RT-PCR amplification of RNA isolated from <i>biceps brachii</i> and <i>tibialis anterior</i> biopsies obtained from CTR and DM1 patients. Bands were quantified and proportions of isoform <i>INSR-B</i> (+exon 11) were calculated. (<b>B)</b> Representative western blot analysis of the expression of proteins involved in the insulin pathway in <i>biceps brachii</i> and <i>tibialis anterior</i> biopsies obtained from CTR and DM1 patients. Due to the high number of samples analysed, the figure panel is composed by images of bands originating from different gels. Details on how western blot experiments were performed are reported in Materials and Methods. (<b>C)</b> Quantification of proteins expression normalized to GAPDH in <i>tibialis anterior</i> biopsies obtained from CTR and DM1 patients. Histograms represent mean values and bars represent standard error of the mean (SEM). (<b>D)</b> Quantification of proteins expression normalized to GAPDH in <i>tibialis anterior</i> and <i>biceps brachii</i> biopsies obtained from two DM1 patients who performed two successive biopsies at different years of age. Data obtained from one BB and one TA sample from DM1-1 and DM1-4 were compared with mean values obtained from 2 CTR BB and 3 CTR TA. Bars represent standard error of the mean (SEM). The number of samples analysed in each group (n) is reported in histogram legends. Differences between groups have been evaluated by Student <i>t</i>-test. *p<0.05; **p<0.01.