title: Sex-specific expression, synthesis and localization of aromatase regulators in one-year-old Atlantic salmon ovaries and testes.
abstract: 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. The activity of two forms, cyp19a and cyp19b1, is predominantly associated with the ovary and the brain, respectively. We isolated sequences that compose the proximal promoters of cyp19a, cyp19b1 and foxl2a, to identify potential transcription factor binding motifs to define sex-specific regulatory profiles for each gene. We also provide evidence for the translation and immunological localization of DAX-1, FOXL2 and MIS to the endoplasmic reticulum and accumulation within secretory vesicles of the salmon oocyte. We found no evidence for the expression of CYP19A or CYP19B1 in the oocyte at the one-year-old stage. However, synthesis of both aromatases was localized to testicular germ and soma cells at this early stage of development. Production of these regulatory factors in the germ cells may serve to modulate the transcription and activity of endogenous aromatase and/or contribute to the differentiation of the neighbouring companion cells through secretory signaling.
authors: Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada V8W 3N5; Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6. Electronic address: krvs@uvic.ca.
authors: Kristian R
authors: KR
authors: von Schalburg
authors: Department of Biology, Electron Microscopy Laboratory, University of Victoria, Victoria, British Columbia, Canada V8W 3N5.
authors: Brent E
authors: BE
authors: Gowen
authors: Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada V8W 3N5.
authors: Eric B
authors: EB
authors: Rondeau
authors: Microtek Research and Development Ltd., 6761 Kirkpatrick Crescent, Victoria, British Columbia, Canada V8X 3X1.
authors: Norman W
authors: NW
authors: Johnson
authors: Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada V8W 3N5.
authors: David R
authors: DR
authors: Minkley
authors: Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada V8W 3N5.
authors: Jong S
authors: JS
authors: Leong
authors: Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
authors: William S
authors: WS
authors: Davidson
authors: Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada V8W 3N5.
authors: Ben F
authors: BF
authors: Koop
mesh_terms: D000818:Animals; D001141:Aromatase / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D057137:DAX-1 Orphan Nuclear Receptor / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005260:Female; D005854:Germ Cells / Q000378:metabolism; D008297:Male; D009928:Organ Specificity; D010053:Ovary / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D018000:Receptors, Peptide / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D020317:Salmo salar / Q000378:metabolism*; D012733:Sex Differentiation; D013737:Testis / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D057137:DAX-1 Orphan Nuclear Receptor; D018000:Receptors, Peptide; D018125:Receptors, Transforming Growth Factor beta; D014157:Transcription Factors; C084621:anti-Mullerian hormone receptor; D001141:Aromatase
keywords: Gene expression; Immunolabeling; Ovary; Promoter; Testis