Pitx3-Cre driven eYfp expression starts between E12.5 and E13.5 and marks the ventral tegmentum, overlapping with Th.

<p>A) Th and eYfp co-localization in sagittal sections of the ventral mesodiencephalic region. Note that at this stage eYfp is not detected. B) Th and eYfp seperate as well as co-localization in sagittal sections of the ventral mesodiencephalic region. At this stage co-localization can be found but also some areas where Th and eYfp are uncoupled. C) Similar analysis as in B, on E14.5 material, confirming the Yfp and Th distribution. The white arrows indicates a medial/rostral region where Yfp is expressed in cells that do not express Th. L: lateral; M: medial.</p

Pitx3-Cre driven expression of eYfp co-localizes with all Th positive neurons.

<p>A) Th and eYfp expression in the control LoxP-stop-LoxP-eYfp animal. Note that only Th is expressed in these animals. B) Co-localization of Th and eYfp in the mdDA neuronal region. Note the complete overlap of Th positive neurons with eYfp. C) Enlarged figures of boxes as marked in B. White arrows: indication of the regions and cells where there is eYfp expression with no Th co-localization.</p

Pitx3-Cre driven eYfp expression outside the brain maps to the muscle.

<p>A) Representation of the eYfp muscle expression in the developing embryo at 2 stages of development. B) Enlarged figures of boxes marked in A. C) Schematic representation of the recombinant knock-in construct indicating the position and the 3′-restricted flank of the alternative exon1 position. Figure details as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042641#pone-0042641-g001" target="_blank">figure 1</a>.</p

Pitx3-Cre driven expression of eYfp marks transient expression of Pitx3 in a medial non-dopaminergic cell-group.

<p>A) In depth analysis through Th and eYfp co-localization of non-dopaminergic regions that express eYfp. B) Enlarged figures of boxes marked in A. C) Co-localistion of Yfp with 5-Ht staining at 4 separate A/P positions from left to right (top 4 panels). Higher magnification of the boxed areas are presented in the lower 2 panels, clearly showing that the Yfp positive neurons do not co-localise with 5-HT neurons. IF: interfascicular nucleus; IPF: interpeduncular fossa; RLi: rostral linear nucleus of the raphe; CLi:caudal linear nucleus of the raphe.</p