FIGURE SUMMARY
Title

Characterization of embryonic globin genes of the zebrafish

Authors
Brownlie, A., Hersey, C., Oates, A.C., Paw, B.H., Falick, A.M., Witkowska, H.E., Flint,J., Higgs, D., Jessen, J., Bahary, N., Zhu, H., Lin, S. and Zon, L.
Source
Full text @ Dev. Biol.

Whole-mount in situ hybridization analysis of embryonic globin gene expression in the zebrafish. Expression of the embryonic globin genes αe1/αe2 (A, F, K, P), αe3 (B, G, L, Q), βe1 (C, H, M, R), βe2 (D, I, N, S), and βe3 (E, J, O) were examined at 24 (A–E), 48 (F–J), 72 (K–O), and 120 hpf (P–S) by whole-mount in situ hybridization. The sequence of the αe1- and αe2-globins is highly similar, and so it is unlikely that these mRNAs can be distinguished by using this technique. The expression of βe3-globin has not been examined at 120 hpf.

Analysis of globin gene expression in zin mutants by whole-mount in situ hybridization analysis. At 18 hpf, no defect in the expression of αe3-globin (A), βe2-globin (B), or GATA-1 (C) can be detected in clutches arising from an intercross of two zin AB/SJD heterozygotes. GATA-1 is shown as a control for erythroblast number; at this stage, no cell lysis is apparent in zin mutant embryos. At 24 hpf, expression of αe3-globin (D, E) and βe2-globin (F, G) is reduced in zin homozygotes. This effect is likely to be due to a decrease in red blood cell number, as shown by reduced expression of the erythroid marker jak2a in zin homozygotes (H, I). By 36 hpf, levels of αe3-globin and βe2-globin mRNA can be used to distinguish wild-type siblings (J, M), zin heterozygotes (K, N), and zin homozygotes (L, O). The reduction in staining in the mutant embryos is reflective of the severity of the anemia at this stage and represents a secondary effect of cell lysis.

zin is linked to the LG 3 globin locus. (A) SSCP within the βe1-globin gene(s) segregates in the offspring of a zin Tu/Dar X AB outcross. A marker corresponding to a Dar allele of this amplicon segregates with respect to phenotype (1/299 recombinants) (arrow). (B) Stick diagram of LG3 chromosome with localization of the zin gene.

Acknowledgments
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Reprinted from Developmental Biology, 255(1), Brownlie, A., Hersey, C., Oates, A.C., Paw, B.H., Falick, A.M., Witkowska, H.E., Flint,J., Higgs, D., Jessen, J., Bahary, N., Zhu, H., Lin, S. and Zon, L., Characterization of embryonic globin genes of the zebrafish, 48-61, Copyright (2003) with permission from Elsevier. Full text @ Dev. Biol.