Figure 6.

N3 cis-regulatory elements from either nematodes or vertebrates drove expression equivalently. (A) MUSSA analysis was used to identify any ungapped matches between nematodes and various vertebrates. Synteny of two elements, N3 and N7 highlighted by red boxes, suggested the match was not noise. All figures are to the same scale (hash marks represent 50-kb distances), with the regions examined in each case bounded by the next 5′ or 3′ curated genes on the chromosome. The Hox genes are color coded: (red) HOXA1, (orange) HOXA2, (yellow) HOXA3, (green) HOXA4, (blue) HOXA5, (purple) HOXA6. (B) Apparent conservation of N3 among vertebrates was very high, with similarity still at 100% in a 30-bp window. Vertical red lines represent base conservation between all six species. (C) N3 sequences shared 75% identity, using a 20-bp window, across 11 vertebrate and nematode species. (D) A mouse N3-like region drove expression in C. elegans that was almost identical to that driven by the C. elegans N3 region. Expression is seen in L1 larvae in the V cells on the left (D1, D3), and P cells and hypodermal syncytium on the right (D2, D4). Additional expression in observed in the head with the mouse construct. Scale bars, 10 microns.