Expression patterns of sept6 during zebrafish embryonic development. (A) Expression patterns of sept6 at different stages were assessed by RT-PCR, with β-actin as the control. (B to M) WISH analysis of zebrafish sept6 expression levels at different developmental stages. (B) Four-cell stage, top view; (C) 256-cell stage, lateral view; (D) shield stage, lateral view; (E) 85% epiboly stage, dorsal view; (F) 4-ss stage, dorsal view; (G) 4-ss stage, lateral view; (H) 16-ss stage, dorsal view; (I) 16-ss stage, lateral view; (J) prim-15 stage, front view; (K) prim-15, lateral view; (L) prim-15, cross-section view; (M) long-pec stage, lateral view. Abbreviations: NC, notochord; SCN, spinal cord neuron; MHB, midhindbrain boundary; INL, inner nuclear layer; OB, olfactory bulb; NT, neural tube; SCPZ, spinal cord proliferative zone; GL, glomerulus; PT, pronephric tubule; PD, pronephric duct.