May participate in a function common to the expression of most genes transcribed by RNA polymerase II. Ubiquitous. Enriched in the brain and central nervous system during embryogenesis. Enriched in the adult head. Embryos contain both isoforms A and B, whereas later in development (heads and torsos) only isoform B is detected. Expressed in the developing embryo from the earliest stages of cellularization and is subsequently found in many cell types. 'Cabeza' means 'head' in Spanish. Belongs to the RRM TET family. Wrong choice of frame.