The optic disc (often called the `blind spot') is where optic fibres converge and leave the retina, and, on , Bovolenta and co-workers shed light on its formation. It develops from the edges of a groove (called the optic fissure) at the ventral pole of the rudimentary eye,and its position is determined by the juncture of two distinct regions of the optic fissure - the retinal fissure and the optic groove. Having found that retinal fissure precursors express a unique combination of markers (including PAX2), the researchers studied these precursors in mice that lack BMP7. This analysis revealed that BMP7 is required for the specification of retinal fissure precursors and that it regulates their subsequent proliferation and apoptosis. SHH, they report, is also required for retinal fissure precursor maintenance during development. And because the microphthalmic (small eye)phenotype of BMP7-null mice resembles a rare congenital disease in humans, the authors also speculate on the role of BMP7 in this type of abnormality.
