Hypothalamic peptide expression in zebrafish knockdown for MYT1L orthologues.

(A)Whole mount in situ hybridization demonstrating that MYT1L orthologs myt1la and myt1lb are expressed throughout the zebrafish central nervous system. T = telencephalon, te = tectum, hy = hypothalamus, h = hindbrain. (B)Whole mount in situ hybridization demonstrating loss of myt1la expression in arnt2 mutant zebrafish, top panel shows control fish and bottom panel arnt2 mutant fish. The embryos are heavily over-stained to show the low-level expression of myt1la in the ventral diencephalon. The arrow indicates the region of the neuroendocrine preoptic area where oxytocin expressing neurons are located. (C)Whole mount in situ hybridization demonstrating that knockdown of myt1la and myt1lb, alone or in combination, results in loss of oxytocin expression in the neuroendocrine preoptic area. Arrows indicate neuroendocrine preoptic area. (D)Bar chart quantifying loss of oxytocin expression in neuroendocrine preoptic area. WISH for oxytocin was quantified as follows: ~30 cells = wild type expression, 5–15 cells = reduced, 1–4 = highly reduced, 0 = no expression (E)Whole mount in situ hybridization demonstrating that knockdown of myt1la/b results in loss of arginine vasopressin expression in the neuroendocrine preoptic region (indicated by arrow) but not the ventral hypothalamus (indicated by arrowhead). (F) Bar chart quantifying loss of arginine vasopression expression in myt1la/b morphants. WISH for arginine vasopressin was quantified as follows: ~30 cells = wild type expression, 5–15 cells = reduced, 1–4 = highly reduced, 0 = no expression.