Genomic organization and alternative splicing pattern of Spatial gene in the mouse. (A) The mouse genomic sequence corresponding to the Spatial gene constituted of 10 exons. Alternative spliced exons are represented by blue boxes and common exons of the different Spatial isoforms are represented by gray boxes. Green and red arrows correspond to the designed primers specific for the Spatial short and long isoforms respectively used for the quantitative TaqMan RT-PCR experiment. (B) mRNA organization of Spatial isoforms: the Spatial short mRNA isoforms (Spatial-α, -β, -γ) differ by a 102 bp additional exon for Spatial-α and 69 bp for the newly described Spatial-β comparing to the shortest Spatial-γ isoform. The NLS encoding sequence is represented by a yellow box, specific for short isoforms. The Spatial-δ isoform differs from Spatial-ε isoform by a 102 bp additional exon. The predicted start codon indicated by (Δ) and the stop codon indicated by (*) are localised in exon 2 and exon 5 for short isoforms and in exon 1 and exon 10 for long isoforms, respectively. Long and short isoforms differ by the addition of 5 exons in the 5'end of long isoforms.