Conserved modularity and potential for alternate splicing in mouse and human Slit genes.
The vertebrate Slit gene family currently consists of three members; Slit1, Slit2 and Slit3. Each gene encodes a protein containing multiple epidermal growth factor and leucine rich repeat motifs, which are likely to have importance in cell-cell interactions. In this study, we sought to fully define and characterise the vertebrate Slit gene family. Using long distance PCR coupled with in silico mapping, we determined the genomic structure of all three Slit genes in mouse and man. Analysis of EST and genomic databases revealed no evidence of further Slit family members in either organism. All three Slit genes were encoded by 36 (Slit3) or 37 (Slit1 and Slit2) exons covering at least 143 kb or 183 kb of mouse or human genomic DNA respectively. Two additional potential leucine-rich repeat encoding exons were identified within intron 12 of Slit2. These could be inserted in frame, suggesting that alternate splicing may occur in Slit2. A search for STS sequences within human Slit3 anchored this gene to D5S2075 at the 5' end (exon 4) and SGC32449 within the 3' UTR, suggesting that Slit3 may cover greater than 693 kb. The genomic structure of all Slit genes demonstrated considerable modularity in the placement of exon-intron boundaries such that individual leucine-rich repeat motifs were encoded by individual 72 bp exons. This further implies the potential generation of multiple Slit protein isoforms varying in their number of repeat units. cDNA library screening and EST database searching verified that such alternate splicing does occur.
Little
Melissa
M
Institute for Molecular Bioscience and Centre for Functional and Applied Genomics, University of Queensland, St Lucia, Australia. M.Little@imb.uq.edu.au
Rumballe
Bree
B
Georgas
Kylie
K
Yamada
Toshiya
T
Teasdale
Rohan D
RD
D020413:3' Untranslated Regions; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002874:Chromosome Mapping; D002895:Chromosomes, Human, Pair 5; D018076:DNA, Complementary / Q000378:metabolism; D005091:Exons; D020224:Expressed Sequence Tags; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007438:Introns; D007930:Leucine / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics*; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D020033:Protein Isoforms; D017386:Sequence Homology, Amino Acid; D000098552:Slit Homolog 2 Protein
D020413:3' Untranslated Regions; D018076:DNA, Complementary; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; C492289:SLIT1 protein, human; C498990:SLIT3 protein, human; C120010:Slit1 protein, mouse; C432251:Slit3 protein, mouse; D007930:Leucine; D000098552:Slit Homolog 2 Protein