A phospholipase A2-like pseudogene retaining the highly conserved introns of Mojave toxin and other snake venom group II PLA2s, but having different exons
| Autor: | Ted R. John, James J. Smith, Ivan I. Kaiser |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Pseudogene
Molecular Sequence Data Neurotoxins Restriction Mapping Venom Phospholipases A Exon Sequence Homology Nucleic Acid Crotalid Venoms Genetics Viperidae Animals Amino Acid Sequence Cloning Molecular Molecular Biology Gene Conserved Sequence Phylogeny biology Base Sequence Sequence Homology Amino Acid Crotalus Intron Cell Biology General Medicine Exons Sequence Analysis DNA biology.organism_classification Noncoding DNA Molecular biology Introns Phospholipases A2 Snake venom Crotalus scutulatus lipids (amino acids peptides and proteins) Pseudogenes |
| Zdroj: | DNA and cell biology. 15(8) |
| ISSN: | 1044-5498 |
| Popis: | Mojave toxin is a neurotoxic, heterodimeric phospholipase A2 (PLA2) from the venom of the Mojave rattlesnake (Crotalus scutulatus scutulatus) and is characteristic of all rattlesnake presynaptic neurotoxins. Here, we describe a phospholipase A2 pseudogene (psi-Mtx) located 2,000 nucleotides upstream, and on the opposite DNA strand, from a gene for Mojave toxin acidic subunit (Mtx-a). The pseudogene lacks the first exon and a few segments of noncoding DNA found in functional snake venom PLA2 genes, but does have the coding information for a complete PLA2 protein. psi-Mtx retains the unusual gene sequence similarity pattern found in functional viperid PLA2 genes. When compared to genes from C. s. scutulatus and the Hahn snake (Trimeresurus flavoviridus), psi-Mtx shows strong conservation of nocoding regions and variable protein-coding regions. Although the nocoding regions of psi-Mtx are conserved with respect to other viperid PLA2 genes, the three exons code for a unique PLA2-like protein similar in sequence to ammodytoxin b found in the venom of the western sand viper (Vipera ammodytes ammodytes). The structure of these genes suggests a common ancestor for all viperid PLA2 genes. Phylogenetic analysis of psi-Mtx, Mtx-a, Mtx-b, pgPLA 1a, and pgPLA 1b suggest that psi-Mtx diverged from an ancestral sequence before the presumed gene duplication event leading to Mtx-a and Mtx-b. However, analysis of the basis of coding regions alone gives a conflicting result. |
| Databáze: | OpenAIRE |
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