Alternative Splicing of Titin mRNA in Rat Soleus after Seven-Day Gravitational Unloading

Changes in titin alternative splicing in the rat soleus after seven-day gravitational unloading (the hindlimb unloading model) were studied by long-fragment PCR and nanopore sequencing. An increase in the proportion of shorter titin mRNA transcripts was found in m. soleus of the hindlimb suspended rats, which may have led to the translation of shorter variants of the N2A isoform of this protein. In the nuclear fraction of m. soleus of control and hindlimb suspended rats, no significant differences were found in the content of Rbm20, an RNA-binding protein involved, as is shown earlier, in the regulation of titin alternative splicing in mammalian cardiac muscle. It can be assumed that Rbm20 is not involved in the regulation of titin alternative splicing in the rat soleus muscle.