temca Encodes the VGSC alpha subunit, scn8ab. (A, Top) Schematic of Scn8ab (Nav1.6) protein structure. Red arrow points to temca mutation in pore-loop (P-loop) of the third domain. Deleted region of scn8ab deletion allele (scn8abΔ) is shown. (Middle) sgRNA target sites are depicted for 5.7-kb deletion of scn8ab and primers used to confirm deletion. (Bottom) A representative DNA gel image indicating scn8abΔ is shown. (B) Sanger sequencing chromatograms from control (wild-type siblings) and temca. The temca mutation within the scn8ab coding sequence causes an asparagine (N) to lysine (K) change. (C) Amino acid sequence alignment across distant species. Black boxes mark conserved residues. Red box and arrow indicate temca N to K mutation. (D–H) Complementation analysis for temca and scn8abΔ. (D) Swimming behavior of control (scn8ab+/Δ) and scn8ab compound heterozygotes (scn8abtemca/Δ) at 33 °C. (Bottom) Representative 1-min swimming trajectories of individual fish. (E and F) Quantification of 3-min swimming behavior at 33 °C. (E) Average distance traveled (n = 6). (F) Duration of immobility at the bottom of swimming tanks (n = 6). (G–I) Regeneration in scn8abtemca/Δ normalized to uninjured fin lengths. (G) Representative whole-mount fin images of 7 dpa control and scn8abtemca/Δ at 33 °C. (H) Fin lengths at 7 dpa (b in G) normalized to uninjured fin length (a in G). The graph indicates the value of “b/a”. (I) Position of amputation plane. Lengths from base to amputation plane (c in G) were divided by uninjured fin lengths (a in G). The graph indicates the value of “c/a”. The amputation plane was ∼50% of caudal fins in control and scn8abtemca/Δ. n = 8 and 6 for control and scn8abtemca/Δ, respectively. Data are presented as mean ± SD. Student’s unpaired two-tailed t test.
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