Rfx2 is required for spermatogenesis in the mouse.

RFX transcription factors are key regulators of ciliogenesis in vertebrates. In Xenopus and zebrafish embryos, knockdown of Rfx2 causes defects in neural tube closure and in left-right axis patterning. To determine the essential role of the Rfx2 gene in mammalian development, we generated Rfx2-deficient mice using an embryonic stem cell clone containing a lacZ gene trap reporter inserted into the first intron of the Rfx2 gene. We found that the Rfx2 lacZ reporter is expressed in ciliated tissues during mouse development including the node, the floor plate and the dorsal neural tube. However, mice homozygous for the Rfx2 gene trap mutation did not have defects in neural tube closure or in organ situs. The gene trap insertion appears to create a null allele as Rfx2 mRNA was not detected in Rfx2gt/gt embryos. Although Rfx2-deficient mice do not have an obvious embryonic phenotype, we found that Rfx2gt/gt males are infertile because of a defect in spermatid maturation at or before the round and elongating spermatid stage. Our results indicate that Rfx2 is not essential for embryonic development in the mouse but is required for spermatogenesis. genesis 53:604-611, 2015.