The myosin alkali light chains of XXXX ventricular and slow skeletal muscle are indistinguishable and are encoded by the same gene.

@entity48684 @entity19759 @entity19 @entity48668
We have isolated a cDNA recombinant plasmid (pA29) identified as encoding part of the ventricular muscle myosin light chain @entity48684 . This cDNA contains a 300-base pair fragment which under conditions of moderate stringency shows specific hybridization to @entity48684 mRNA with no detectable cross-hybridization with the mRNAs encoding the fast skeletal muscle isoforms MLC1F and @entity19759 , or the atrial muscle isoform @entity48668 . Under these conditions hybridization is seen with an abundant mRNA present in slow skeletal muscle (soleus) which is indistinguishable from ventricular @entity48684 mRNA on the basis of size and of thermal stability of hybrids formed with plasmid pA29. The @entity19 @entity48684 and @entity48684 proteins are found to co-migrate on two-dimensional gels. We therefore conclude that these isoforms are the same and are encoded by the same mRNA. Analysis of @entity19 DNA has identified a single region of the genome which hybridizes to this same fragment of pA29. This region has been isolated in a recombinant phage and has been shown to contain a single gene showing homology with @entity48684 mRNA by R-loop analysis. We therefore conclude that @entity48684 and @entity48684 are encoded by a single gene. The pattern of segregation of a restriction fragment length polymorphism identified for this gene between @entity19 and Mus spretus has been followed in an F1 backcross between these two @entity19 species. The results show the @entity48684 / @entity48684 gene to be closely linked to a marker at the distal end of @entity19 chromosome 9.
