Xenbase Image ID: 24015

Fig. 1. Genomic organization of the murine Bmp7 locus and screening strategy used to identify enhancer elements. (A) The Bmp7 gene is comprised of 7 discrete exons distributed over approximately 72 kb on mouse chromosome 2. Exon–intron structure is depicted, with black boxes corresponding to exons comprising the 5′ UTR and encoding mRNA for the prodomain of BMP7 and red boxes corresponding to exons comprising the 3′ UTR and mRNA for the mature domain of BMP7. Bar at top right represents 2.5 kb. (B) Predicted structures of Bmp7 transcripts based on sequencing of newborn kidney cDNA and 3′ RACE of embryonic kidney mRNA: in addition to the previously published initiation site 102 bp upstream of the first AUG (1.9 and 3.6 kb transcripts), an initiation site was identified 372 bp upstream of the AUG (2.1 and 3.8 kb transcripts). Additionally, two 3′ termini were identified: one 448 bp downstream from the UAG stop codon (1.9 and 2.1 kb transcripts), and another 1887 bp downstream from the UAG (3.6 and 3.8 kb transcripts). Red and black regions correspond to red and black exons in panel A. (C) Total RNA was isolated from E13.5, E17.5 and adult kidneys (13.5, 17.5 and ad respectively), and subjected to Northern hybridization with a probe corresponding to the entire Bmp7 coding sequence. Four RNA species were detected; 1.9 kb, 2.1 kb, 3.6 kb and 3.8 kb. Alternate initiation and termination sites shown in panel B account for these four distinct RNA transcripts. (D) Strategy used to screen for enhancer elements driving Bmp7 expression in the developing kidney. The genomic region surrounding Bmp7 exon 1 (bracketed in panel A) is shown, and lines below denote sizes of genomic subclones 142:1, 216:1, 216:2, 217:1 and 217:2. The presence of enhancer elements in each of these subclones was assayed using the Hsp68lacZpA reporter in transgenic mice. Reporter constructs drive expression at diverse anatomical sites. (E) The 216:2 genomic subclone drives expression in neural crest (NC) adjacent to the neural tube (NT). (F) Expression in nephrogenic mesenchyme (NM) of the kidney is driven by the T fragment. (G, G') Expression in collecting ducts (CD) of the kidney is driven by the 217:1 fragment. Image published in: Adams D et al. (2007) Copyright © 2007. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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