The tripartite motif (TRIM) family of proteins are characterized by a conserved TRIM domain that includes a coiled-coil region, a B-box type zinc finger, one RING finger and three zinc-binding domains. TRIM61 (Tripartite motif-containing protein 61), also known as RNF35 (RING finger protein 35), is a 209 amino acid protein that contains a variety of domains that are characteristic to TRIM proteins, including a RING-type zinc finger and a B box-type zinc finger. In mice, TRIM61 is temporarily transcribed in the early embryo, but then is permanently silenced before the blastocyst stage of development. Transcription of TRIM61 is positively regulated by nuclear factor Y (NF-Y). The gene encoding TRIM61 maps to human chromosome 4, which encodes nearly 6% of the human genome and has the largest gene deserts (regions of the genome with no protein encoding genes) of all of the human chromosomes.