Fig. 1
Structure and transcripts of the Skt/Etl4 gene. a Scheme of mouse chromosome 2 with the integration sites of Enhancer trap locus 4 (Etl4lacZ) and Sickle tail (SktGt). Above the scheme the distribution of Skt/Etl4 exon sequences obtained from GenBank/NCBI entries NM_178059.5 (Etl4-a), NM_029895.4 (Etl4-b), NM_001081006.1 (Etl4-c), NM_001177630.2 (Etl4-d), NM_001177631.1 (Etl4-e), BC158051.1, BC050016.1, BC026657.1, AB125594.2 (Skt-a), AB125595.2 (Skt-b) is shown, below the exon distribution of Riken cDNA clones mpm09263 and mbg07236. The new exons 1 and 2 located 360 kb and 168 kb upstream of the already published Skt/Etl4 mRNA are indicated in red. b Schematic representation of Riken cDNA clones mpm09263 (4573 bp) and mbg07236 (5659 bp). Squares represent exons (drawn at scale) with continuous numbering above and sizes in bp below. Above exon 1, 2, 3 the location of the primer pair used in (c) is indicated. Grey squares: open reading frame with the respective N- and C-terminal amino acid sequences indicated below. Stippled box: proline-rich region. Black box: coiled-coil region. Red box: new exons 1 and 2. c RT-PCR with primers located in exon 1 and 3 (depicted in (b)) with poly (A+) RNA isolated from adult brain and embryo stage E9.5. Negative control (water) contains no cDNA. Red arrowhead marks PCR product used for sub-cloning and sequencing. d Northern blots with adult testis (Te), spleen (Sp) and kidney (Ki) poly (A+) RNA hybridized with Skt/Etl4 probes specific for exons indicated above. Detected transcripts of around 7, 6, 4, 3 and 1 kb in size are indicated by black arrowheads. e Northern blot with poly (A+) RNA from various embryo stages (indicated below) hybridized with exon 5-8 specific probe shows approx. 8 and 7 kb transcripts (arrowheads). f Whole mount in situ hybridization of wild type stage E9.5 embryos (a, b) with Skt/Etl4 exon-specific probes indicated at the top