Differential pre-mRNA defects in fission yeast carrying a temperature degron allele of the SMN gene

The SMA disease results from deletions or mutations in the “survival of motor neuron” (SMN1) gene. The SMN protein plays an essential role in the biogenesis of spliceosomal snRNPs but the link between a defect in this process and specific splicing inhibition is not known. Here, we report the construction of a temperature degron (td) allele of the S. pombe SMN protein and show that its depletion at 37°C affects snRNPs stability and splicing. In addition, the function of the tdSMN allele in snRNPs assembly is affected already at 25°C suggesting a deleterious effect of the tag at this temperature. Remarkably, using S. pombe tiling arrays and RT-PCR validation tests, we report that splicing is altered differentially in the tdSMN cells at permissive temperature. Our results suggest that the defects observed in tdSMN fission yeast cells mimic splicing deficits observed in SMN-deficient metazoan cells. Total RNA (triplicate experiment) from the td-SMN strain grown at 25°c vs total RNA from the wild type strain (triplicate experiment)