Figure 2.

Nmr1 and Nmr2 protein expression during embryogenesis.

Nmr2 (A–D,L), Nmr1 (E–H,I) and nmr1 mRNA transcript (E′–H′) expression in wild-type embryos at progressively later stages of development (A) Stage 9 embryos express Nmr2 in segment polarity stripes. (B) During early stage 12, Nmr2 is expressed in subsets of neuroblasts and their progeny in the CNS (arrows) as well as in heart precursor cells in the dorsal mesoderm (arrowheads). (C) During late stage 12, Nmr2 is expressed prominently in a medial pair of CNS neurons in each segment (arrows) and is also expressed in heart precursor cells (arrowheads). (D) By stage 16 Nmr2 is expressed in many neurons in the CNS (brackets), narrower transverse stripes of ectodermal cells (white arrows), and clusters of ectodermal cells (white arrowheads) between these stripes. (E) Stage 9 embryos do not express Nmr1 protein while (E′) nmr1 transcripts are clearly detected in segment polarity stripes. (F) Nmr1 protein is first detected during early stage 12 in a few cells in the cephalic region (arrow), (F′) while similarly staged embryos express nmr1 transcripts in segment polarity stripes, neuronal precursors and neurons. (G, G′) By stage 13, Nmr1 protein and RNA are expressed in identical patterns of CNS neurons (arrows) and heart precursors in the mesoderm (arrowheads). (H, H′) By stage 16, Nmr1 protein and RNA are co-expressed in many neurons in the CNS (H, brackets), all cardioblasts as well as in narrow stripes of ectodermal cells (H, white arrows). (I–N) High magnification views of the Drosophila heart at stage 16 show that Nmr1 (I, green; M, red) and Nmr2 (L, green) are co-expressed with Mef-2 (J, red) in all cardioblasts (K,N). Whole mounts in the lateral orientation; Anterior, left; Posterior, right; Dorsal, up; Ventral, down.