Spatiotemporal expression of Math6 during mouse embryonic development.

The basic helix-loop-helix transcription factor Math6 was shown to have important regulatory functions during many developmental events. However, a systematic description of Math6 expression during mouse embryonic development is up to now still lacking. We carried out this study to show Math6 expression at different stages of mouse embryonic development aiming to provide a wide insight into the regulatory functions during the mouse organogenesis. Using immunohistochemistry, we could show that Math6 expression is activated in the inner cell mass at the blastocyst stage and in the neural tube as well as somatic and splanchnic mesoderm at stage E8.5. At stages E8.5 and E10.5, Math6 transcripts were detected in the myotome, neural tube, pharyngeal arches, foregut and heart. At stages E11.5 and E12.5, Math6 transcripts were accumulated in the developing brain, heart, limb buds and liver. The heterozygous transgenic mouse embryos carrying EGFP-Cre under the Math6 promoter were used to analyze Math6 expression at later stages by means of immunohistochemistry against EGFP protein. EGFP was observed in the neural tube, heart, lung, skeletal muscle, skin, cartilage, trachea and aorta. We have observed Math6 expression in various organs at early and late stages of mouse development, which illustrates the involvement of Math6 in multiple developmental events.