About Sonic Hedgehog
This gene encodes a protein that is instrumental in patterning the early embryo. It has been implicated as the key inductive signal in patterning of the ventral neural tube, the anterior-posterior limb axis, and the ventral somites. Of three human proteins showing sequence and functional similarity to the sonic hedgehog protein of Drosophila, this protein is the most similar. The protein is made as a precursor that is autocatalytically cleaved; the N-terminal portion is soluble and contains the signalling activity while the C-terminal portion is involved in precursor processing. More importantly, the C-terminal product covalently attaches a cholesterol moiety to the N-terminal product, restricting the N-terminal product to the cell surface and preventing it from freely diffusing throughout the developing embryo. Defects in this protein or in its signalling pathway are a cause of holoprosencephaly (HPE), a disorder in which the developing forebrain fails to correctly separate into right and left hemispheres. HPE is manifested by facial deformities. It is also thought that mutations in this gene or in its signalling pathway may be responsible for VACTERL syndrome, which is characterized by vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, radial and renal dysplasia, cardiac anomalies, and limb abnormalities. Additionally, mutations in a long range enhancer located approximately 1 megabase upstream of this gene disrupt limb patterning and can result in preaxial polydactyly. [provided by RefSeq, Jul 2008]

About Alexa Fluor 488
Alexa Fluor™ 488 (AF488, Alexa 488) has an excitation peak at 488 nm and an emission peak at 496 nm, and is considered a high-performance alternative to FITC. Alexa 488 is one of the most popular Alexa Fluor™ dyes and is widely used in Fluorescence Microscopy, flow cytometry, and for staining low expression markers. It is bright, highly photostable, resistant to pH changes, and less susceptible to photobleaching. Alexa 488 and is similar in size, brightness and application to DyLight™ 488, iFluor® 488 and CF®488A.