The proneural basic helix-loop-helix (bHLH) proteins promote neurogenesis by inducing changes in gene expression required for neuronal differentiation. Here we characterize one aspect of this differentiation program by analyzing a small family of putative corepressors encoded by MTG genes. We show that MTG genes are expressed sequentially during neurogenesis as cells undergo neuronal differentiation in both the chick spinal cord and in the Xenopus primary nervous system. Using in ovo electroporation, we show that misexpressing wild-type forms of MTG proteins in the developing chick spinal cord does not detectably alter neuronal differentiation. By contrast, the number of differentiated neurons is markedly reduced when a putative dominant-negative mutant of the MTG proteins is expressed in neural precursors in a manner that can be rescued by wild-type MTGR1. Together, these results suggest that MTG family members act downstream of proneural proteins, presumably as corepressors, to promote neuronal differentiation.
Bibliographical noteFunding Information:
We thank Anne Bang (Salk Institute) for the Elr-C probe, critical discussion, and comments on the paper. We also thank Issay Kitabayashi (National Cancer Center Research Institute, Japan) for anti MTG antibodies, Masato Nakafuku (Cincinnati Childrens' Hospital) for anti-Prox1 antibody, and David Anderson (Caltech) for anti-cNgn2 antibody. We are grateful to Elise Lamar for critical discussion and comments on the manuscript. N.K.N. was supported in part by Minnesota Medical Foundation and by Grant-in-aid of Research, Artistry and Scholarship Program from University of Minnesota Graduate School. This work was carried out in part using software provided by the University of Minnesota Supercomputing Institute.
- In ovo electroporation
- MTG/ETO family protein