Figure 3.

Expression of Groucho-related genes (Grg). (A) Stage VI oocyte with Grg4 transcripts enhanced on animal (an) side [Side view]. (B) 8-cell embryo with maternal ESG1 transcripts enhanced in the animal blastomeres [Side view]. (C) In the blastula, animal cap ectoderm expresses Grg5 [Side view]. (D) In the gastrula, the entire ectoderm expresses Grg4, whereas the pre-involuted mesoderm (meso) and endoderm do not [Side view]. At neural plate stages, Grg4 (E), ESG1 (F) and Grg5 (G) are expressed in the neural plate and PPE; Grg5 is also expressed in the cement gland [Anterior views]. (H) ESG1 is expressed throughout the neural tube, but most strongly in the anterior part (ant. nt). It is also detected in the neural crest (nc), dorsal epidermis (epi) and somites [Dorsal view]. (I) At tail bud stages, ESG1 expression is strong in the entire neural tube, migrating neural crest, somites, otocyst and tail bud (tb) [Side view]. (J) At tail bud stages, Grg4 is weakly detected in the cement gland [Ventral view]. (K) At larval stages, Grg4 is expressed throughout the brain (b), retina (r), placode derivatives (crg, L, olf, oto) and the branchial arches (BA) [Side view]. (L) ESG1 is expressed in the same tissues, and also is detected in the heart (h), ventral gut (vg), nephric mesoderm and the initial outgrowth of the lateral line (LL) [Side view]. In transverse sections at the levels of the anterior trunk (M), forebrain (N, O, P) and hindbrain (Q, R), expression of the various Grg-related genes is noted in the nephric mesoderm, forebrain (fb), hindbrain (hb), retina, branchial arches, cement gland, various placodes (olf, oto, IXg, epibranchial {ebp}) and heart.