- Fxr1 knockout mice show a striated muscle phenotype: implications for Fxr1p function in vivo. Mientjes, E.J., Willemsen, R., Kirkpatrick, L.L., Nieuwenhuizen, I.M., Hoogeveen-Westerveld, M., Verweij, M., Reis, S., Bardoni, B., Hoogeveen, A.T., Oostra, B.A., Nelson, D.L. Hum. Mol. Genet. (2004)