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Fig. 4. Two color fluorescent in situ of collectrin contrasted to other pronephric marker genes. The developmental stage of each sample is indicated in the top right corner of each panel (Nieuwkoop and Faber, 1994). The first column to the left (A, E, I, M) shows collectrin expression in red, the second column (panels B, F, J, N) nkcc2/slc12a1, a segmental marker, in green. The third column from the left (C, G, K, O) illustrates an overlay of these expression patterns, with regions of overlap appearing yellow. The last column (D, H, L, P) shows Na+K+ATPase expression in green. The bottom row (M–P) is a magnified view of (I–L), displaying the pronephros. pt, proximal tubules. Collectrin is first detected with fluorescent in situ at approximately stage 28, and increases in subsequent stages. Collectrin, as compared with Na+K+ATPase, is more uniformly distributed throughout the pronephros (compare M and P), suggesting its use as a general pronephric marker. Furthermore, note the strong expression of collectrin in the proximal tubules (O), unlike the weaker expression of Na+K+ATPase in this region (P). |