Transcription factor that binds to DNA at the 5'-AACAATG-3' consensus sequence (PubMed:10821863, PubMed:15863505, PubMed:16759287, PubMed:17363903). Acts as a transcriptional activator and repressor (PubMed:10821863, PubMed:15863505, PubMed:16759287). Binds synergistically with POU5F1 (OCT3/4) to gene promoters (PubMed:15863505). Binds to the FOXK1 promoter and recruits FHL3, resulting in transcriptional activation of FOXK1 which leads to myoblast proliferation (PubMed:17363903). Acts as an inhibitor of myoblast differentiation via transcriptional repression which leads to down-regulation of the muscle-specific genes MYOD and MYOG (PubMed:10821863). Involved in trophoblast giant cell differentiation via enhancement of HAND1 transcriptional activity (PubMed:16759287). Regulates transcription of HRC via binding to it proximal enhancer region (PubMed:15863505). Involved in skeletal muscle regeneration (PubMed:15367664, PubMed:17363903). Also plays a role in the development of myogenic precursor cells (PubMed:15367664). Interacts with HAND1; the interaction enhances HAND1-induced differentiation of trophoblast giant cells (PubMed:16759287). Interacts with POU5F1 (OCT3/4); binds synergistically with POU5F1 to DNA (PubMed:15863505). Interacts with FHL3; the interaction recruits the transcriptional coactivator FHL3 to the FOXK1 promoter (PubMed:17363903). Expressed in myoblasts (at protein level) (PubMed:15367664). Expressed in embryonic stem cells (at protein level) (PubMed:15367664, PubMed:15863505). Expressed in myogenic progenitor cells (at protein level) (PubMed:17363903). Expressed in the ovary (PubMed:15367664). Expressed in kidney, liver, skeletal muscle, and testes (PubMed:10821863, PubMed:15367664). Expressed in lung and skin (PubMed:15863505). Expressed in the brain, heart, diaphragm, and intestines (PubMed:10821863). Expressed in the conceptus tissues of the placenta (PubMed:16759287). Highly expressed in the conceptus ectoplacental cone of the placenta at embryonic day 7.5 dpc (PubMed:16759287). Expressed in the conceptus trophoblast giant cell layer of the placenta (PubMed:16759287). Expressed in the trophoblast giant cells of the placenta from 10 dpc, expression peaks at 14 dpc, then reduces thereafter to 18 dpc (PubMed:16759287). Expression is increased during trophoblast differentiation (PubMed:16759287). Expressed at 8.5 dpc in developing embryos, with increased expression at 9.5 dpc (PubMed:10821863). Knockout mice are viable, morphologically normal and fertile (PubMed:15367664, PubMed:15863505). Reduced regeneration of damaged skeletal muscle fibers following injury with increased numbers of mononuclear cells and a significant reduction in the number of myofibers (PubMed:15367664, PubMed:17363903). Impaired proliferation of myogenic progenitor cells, reduced number of satellite cells within the tibialis anterior muscles, and a decrease in FOXK1 expression (PubMed:17363903).