DEVELOPMENTAL BIOLOGY. For the article “Differential regulation of midbrain dopaminergic neuron development by Wnt-1, Wnt-3a, and Wnt-5a,” by Gonçalo Castelo-Branco, Joseph Wagner, Francisco J. Rodriguez, Julianna Kele, Kyle Sousa, Nina Rawal, Hilda Amalia Pasolli, Elaine Fuchs, Jan Kitajewski, and Ernest Arenas, which appeared in issue 22, October 28, 2003, of Proc. Natl. Acad. Sci. USA (100, 12747-12752; first published October 13, 2003; 10.1073/pnas.1534900100), the authors note the following error in Fig. 5A. In the real-time RT-PCR experiments, primers against mouse Pentraxin 3 (PTX3, GenBank accession no. X83601) were used instead of primers against rat Pituitary homeobox 3 (Pitx3, a homeodomain transcription factor, GenBank accession no. RNO011005). Real-time RT-PCR with primers against rat Pitx3 (GenBank accession no. RNO011005) showed no difference in Pitx3 mRNA levels upon Wnt-5a treatment of embryonic day (E) 14.5 ventral midbrain (VM) precursor cultures for 3 days. However, Wnt-5a up-regulated mRNA levels of two other dopaminergic markers (tyrosine hydroxylase and c-ret). The corrected figure and legend appear below. The primer sequences for rat Pitx3 are as follows: forward, 5′-TTCCCGTTCGCCTTCAACTCG-3′; reverse, 5′-GAGCTGGGCGGTGAGAATACAGG-3′.
Fig. 5.
Wnts differentially control the development of DA neurons by regulating precursor proliferation and the acquisition of a DA phenotype. Wnt-5a did not affect Ptx3 mRNA expression (A), but up-regulated the expression c-ret (B) and TH (not shown) mRNA, and maintained the expression of GDNF family receptor α1 (GFRα1) mRNA (C) and NCAM mRNA (D) at 3 days in vitro, as assessed by real-time RT-PCR. (E and F) Double immunocytochemistry revealed that Wnt-5a increased the percentage of TH+/Nurr1+ cells in the VM from 50% to 90%. Wnt-1 was less efficient than Wnt-5a, and Wnt-3a actually decreased the proportion of TH+ cells from 50% to 30%. (G and I) Fz8-CRD decreased, in a dose-dependent manner, the proportion of Nurr1+ cells that acquired TH expression in E14.5 VM precursor cultures in the control condition (CP), indicating that Wnt signaling is required for the acquisition of a DA phenotype. (H and I) Treatment of rat E14.5 VM precursor cultures with Fz8-CRD decreased the percentage of TH+/Nurr1+ cells after treatment with Wnt-5a. Statistical analysis and concentrations as in Fig. 4. (J) Model of the mechanisms by which Wnt-1, -3a, and -5a regulate the development of VM DA neurons. Wnt-3a, which is mainly expressed in the dorsal midbrain, enhances the proliferation of Nurr1-expressing precursors and decreases the proportion of neurons that acquire TH expression. Wnt1, probably derived from the midbrain-hindbrain organizer, controls the proliferation of Nurr1-expressing precursors and increases the number of VM neurons. Finally, Wnt-5a specifically increases the number of VM Nurr1-expressing precursors that become TH+ neurons. Note that the size of the arrows correlates with the intensity of the effects.