Fig. 1

Expression patterns of amphioxus Pitx isoforms and TALEN target sites of Pitx gene. a Amphioxus Pitx isoforms. White boxes represent untranslated regions (UTR) and black and red boxes (Pitx homeodomain) represent coding sequences. Broken lines indicate introns. We obtained the partial sequence of Pitxa/b according to available amphioxus EST data and the predicted remaining sequence is supplemented as a dotted slashed box (coding sequence) and dotted white box (UTR). b–b’ Expression of Pitxa/b in left lateral (b–d) and dorsal (b’–d’) views. e–g’ Expression of Pitxc in left lateral (e–g) and dorsal (e’–g’) views. Blue lines in a show the location of Pitxc or Pitxa/b probes and green lines in a show the location of Pitx probe used for whole-mount in situ hybridization (WISH). h Numbers 1, 2, and 3 in a show the location of TALEN target sites in Pitxc and Pitxa/b. Binding sites for TALEN pairs [forward (Fw) and reverse (Rv)] used in this study are highlighted in gray. The SacI, AatII, and TatI restriction site in the spacer is underlined respectively. WT, wild type sequence. A, anterior; P, posterior; D, dorsal; V, ventral; L, left side; R; right side. Scale bars in (b–g’) are 50 μm