Figure 1.

(A) TgMI transgenic construct with the mouse titin promoter (containing 3.57 kb of upstream sequences, the complete noncoding exon 1 and intron 1, and 30 bp partial exon 2 sequence with mutated Ttn ATG to AGT) upstream of a wild-type mouse Ighmbp2 cDNA and an SV40 polyadenylation signal. (B) RT-PCR assay for transgene expression in multiple tissues using transgene-specific primers (exon 1 of Ttn promoter and Ighmbp2 cDNA reverse primer). (C) Live-photograph of a (L to R) B6-nmd mouse along with an unaffected and transgenic TgMI-nmd littermate at 6 weeks of age. Note that the TgMI transgene does not rescue the nmd paralysis phenotype, as the TgMI-Ighmbp2 cDNA is not expressed in spinal cord (see 1B). In contrast, 6-month-old double transgenic TgMI+TgNI-nmd mouse shows complete rescue of both the cardiomyopathy and neurogenic atrophy pictured next to its littermate. (D) Growth curve for the groups of mice in panel C.