High impact information on shhb

• Here, we describe formation of the ZLI in zebrafish in relation to expression of sonic hedgehog (shh) and tiggy-winkle hedgehog (twhh), and to development of the forebrain regions that flank the ZLI: the prethalamus and thalamus [1].
• In contrast, proximal fates were lost in cyclops mutant embryos, which lack twhh- and shh-expressing forebrain cells [2].
• Furthermore, tri and kny have overlapping functions in establishing proper alignment of the anterior neural plate and midline cells expressing shh and twhh genes when the partitioning of the eye primordium takes place [3].
• Deletion analysis showed that distinct regions of the twhh promoter regulated the respective notochord or floor plate specific expression [4].
• The expression pattern of the twhh-GFP transgene mimicked the expression of the endogenous twhh mRNAs in the floor plate, fin buds, branchial arches, retina, and epithelial lining cells of the Kupffer's vesicle [4].

Anatomical context of shhb

• Both shh and twhh are expressed in the embryonic zebrafish retinal pigmented epithelium (RPE), initially in a discrete ventral patch which then expands outward in advance of an expanding wave of photoreceptor recruitment in the subjacent neural retina [5].
• Zebrafish tiggy-winkle hedgehog (twhh) is a member of the hedgehog gene family that plays an important role in patterning brain, neural tube, somites, and eyes [4].

Other interactions of shhb

• In addition, we show that shh and twhh display both unique and redundant functions during diencephalic patterning [1].

References