Embryology Research Today is a free monthly online journal that collates and summarizes the latest research about Embryology, including details on stem cells, reproduction, transplants, cloning.

Identification of a Prosencephalic-Specific Enhancer of SALL1: Comparative Genomic Approach Using the Chick Embryo.

Izumi K, Aramaki M, Kimura T, Naito Y, Udaka T, Uchikawa M, Kondoh H, Suzuki H, Cho G, Okada Y, Takahashi T, Golden JA, Kosaki K

Department of Pediatrics [K.I., M.A., Y.N., T.T., K.K.], Department of Pathology [T.K., Y.O.], Department of Internal Medicine [H.S.], Keio University School of Medicine, Tokyo 160-8582, Japan; Graduate School of Frontier Biosciences [M.U., H.K.], Osaka University, Suita 565-0871, Japan; Department of Pathology [G.C., J.A.G.], Children’s Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia, PA 19104.

Comparative genomics is a promising approach for identifying regulatory elements governing the unique spatio-temporal expression patterns of morphogenetic genes. Conserved noncoding genomic sequences are candidate regulatory elements. Here we performed a survey for conserved noncoding elements (CNE) nested within the SALL1 gene; mutations in this gene result in the Townes-Brocks syndrome. A comparison of the genomic sequence between humans and chicken revealed five CNE. Genomic fragments corresponding to each CNE were inserted into reporter cassettes consisting of eGFP cDNA and a minimal promoter. These constructs were electroporated into chick embryos during gastrula, neurula, and pharyngula stages. Among the five CNE that were examined, one 443 bp CNE exhibited tissue-specific enhancer activity. At the neurula stage, the eGFP signal was visualized in the prosencephalon. At the pharyngula stage, the eGFP signal was confined within the anterior neural ridge, which represents one of the morphogenetic centers regulating the patterning of the anterior neural plate. This report identifies, for the first time, an enhancer element of SALL1.

Published 11 April 2007 in Pediatr Res.
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