Figure 4. Ldb3 is aberrantly spliced in Mbnl3^ΔE2 hearts.

(a) Alternative splicing was analyzed for Ldb3 and Tnnt2 in 11 months male Mbnl3^+/+ (n = 3) and 11 month male Mbnl3^ΔE2 (n = 3) hearts by RT-PCR. Band intensities were quantified by densitometry. Ldb3 exon 11 inclusion in Mbnl3^ΔE2 was significantly decreased when compared to Mbnl3^+/+ hearts. Tnnt2 exon 4 + 5 inclusion was not significantly different in Mbnl3^+/+ and Mbnl3^ΔE2 hearts. Exon numbers and expected band sizes are indicated. The alternatively spliced exon is shown as a gray box. Exon numbers are annotated based on Refseq from UCSC genome browser (NCBI37/mm9). Data are standard error of mean. (b) Expression levels of the alternatively spliced and the constitutive exons of Ldb3 andTnnt2 were quantitated by qPCR using exon-exon boundary spanning primers specific to Ldb3 exon 11 (exons 11–12), and Tnnt2 exon 4 + 5 (exon 3–6) and the constitutive exons (exon 16–17 for Ldb3; exon 7–9 for Tnnt2). Expression levels of each alternatively spliced exon was normalized to that of the corresponding constitutive exon. Relative Ldb3 exon 11 inclusion in Mbnl3^ΔE2 hearts is significantly decreased when compared to Mbnl3^+/+ hearts. Relative Tnnt2 exon 4 + 5 inclusion is not significantly different in Mbnl3^+/+ and Mbnl3^ΔE2 hearts. Data are standard error of mean (n = 3 mice for each genotype, each sample was repeated in triplicate).