Transcription factor that binds to cytidine clusters in double-stranded DNA (PubMed:8647861, PubMed:30487602). Plays a key role in the silencing of unintegrated retroviral DNA: some part of the retroviral DNA formed immediately after infection remains unintegrated in the host genome and is transcriptionally repressed (PubMed:30487602). Mediates transcriptional repression of unintegrated viral DNA by specifically binding to the cytidine clusters of retroviral DNA and mediating the recruitment of chromatin silencers, such as the HUSH complex, SETDB1 and the histone deacetylases HDAC1 and HDAC4 (PubMed:30487602). Acts as an early regulator of adipogenesis by acting as a transcription cofactor of CEBPs (CEBPA, CEBPD and/or CEBPG), controlling the expression of PPARG and probably of other proadipogenic genes, such as SREBF1 (By similarity). May also regulate alternative splicing of target genes during adipogenesis (By similarity). Interacts with FHL2 (PubMed:11813260). Interacts with CEBPA, CEBPD and CEBPG (By similarity). Interacts with MPHOSPH8 and TASOR components of the HUSH complex; leading to recruitment of the HUSH complex (PubMed:30487602). Interacts with SETDB1 (PubMed:30487602). Interacts with HDAC1 (PubMed:30487602). Interacts with HDAC4 (PubMed:30487602). Additional isoforms seem to exist. The matrin-type zinc finger domain is required for localization to nuclear speckles. Tumor-associated antigen found in several cutaneous T-cell lymphoma (CTCL), and in particular in mycosis fungoides patients and in Sezary syndrome patients. Broadly expressed. Contaminating sequence. Potential poly-A sequence.