โ Scribed by Patricia Greenhalgh; Lisa A. Steiner
No coin nor oath required. For personal study only.
Two closely-linked genes, Ragl and Rag2, are required for the recombination of V, D, and J gene segments to form the genes encoding V regions of Igs and T-cell receptors. In several mammalian species, chickens, and Xenopus laevis, the coding region of RAG1 lies within a single exon; its sequence is highly conserved from amphibians to mammals (Schatz et al. 1992;Oettinger 1992). These features suggest that it may be possible to use the polymerase chain reaction (PCR) with degenerate primers to amplify a segment of Rag1 from genomic DNA of more primitive species.
When zebrafish (Danio rerio) DNA was PCR-amplified under conditions similar to those used previously for
Xenopus Ragl (Greenhalgh et al. 1993), with the same degenerate primers, a product of expected size [638 base pairs (bp)] was obtained. Although amplification of nurse shark (Ginglymostoma cirratum) DNA yielded no product of this size detectable by ethidium bromide staining, a faint band migrating at the expected position was detected by Southern blotting with a Xenopus Rag1 probe. This product
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The human recombination activating gene 1 (RAG1) has previously been mapped to chromosomes 14q and 11p. Here we confirm the chromosome 11 assignment by two independent approaches: autoradiographic and fluorescence in situ hybridization to metaphase spreads and analysis of human-hamster somatic cell