Sex-specific expression, synthesis and localization of aromatase regulators in one-year-old Atlantic salmon ovaries and testes.

Transcripts for dax1, foxl2, mis and sf1 are co-expressed in the somatic companion cells of teleost germ cells. These regulatory factors function, in part, to modulate the transcription of aromatase, particularly cyp19a, the terminal enzyme of estrogen biosynthesis. At least two separate aromatase loci exist in teleost fish that encode distinct isoforms.