RESUMO
The FastTag Nucleic Acid Labeling System couples haptens, fluorochromes or affinity ligands to any nucleic acid by attaching a universal, photo-or heat-activatable moiety to which any sulfhydryl-reactive compound can be linked. To demonstrate the versatility of the FastTag system, we have labeled DNA, RNA and oligonucleotide probes with a variety of maleimide-coupled moieties and have used these probes in several applications. In Southern hybridization analyses, RNA probes labeled using FastTag FL (fluorescein) detected 0.04 pg of target DNA. Human satellite DNA clones labeled using FastTag FL or FastTag Biotin detected the corresponding sequences in human chromosome spreads and interphase nuclei by fluorescence in situ hybridization. An antisense oligonucleotide probe cocktail complementary to human proinsulin transcripts labeled using FastTag DNP (dinitrophenyl) detected, in situ, the appropriate transcripts in pancreatic tissue sections. Oligonucleotide primers labeled with FastTag FL were used to PCR-amplify a genomic DNA fragment, which was then detected immunologically. Finally, we discuss how DNA labeled with FastTag Fucose can be bound to a fucose-binding affinity matrix and eluted under mild conditions.
Assuntos
Marcadores de Afinidade/metabolismo , Sondas de DNA/metabolismo , Corantes Fluorescentes/metabolismo , Haptenos/metabolismo , Sondas RNA/metabolismo , Marcadores de Afinidade/síntese química , Azidas/síntese química , Azidas/metabolismo , Southern Blotting , Corantes Fluorescentes/síntese química , Humanos , Hibridização In Situ , Ligantes , Sondas de Oligonucleotídeos/metabolismo , Reação em Cadeia da PolimeraseRESUMO
Screening of a human genomic library with an oligonucleotide probe specific for one of the young subfamilies of Alu repeats (Ya5/8) resulted in the identification of several hundred positive clones. Thirty-three of these clones were analyzed in detail by DNA sequencing. Oligonucleotide primers complementary to the unique sequence regions flanking each Alu repeat were used in PCR-based assays to perform phylogenetic analyses, chromosomal localization, and insertion polymorphism analyses within different human population groups. All 33 Alu repeats were present only in humans and absent from orthologous positions in several nonhuman primate genomes. Seven Alu repeats were polymorphic for their presence/absence in three different human population groups, making them novel identical-by-descent markers for the analysis of human genetic diversity and evolution. Nucleotide sequence analysis of the polymorphic Alu repeats showed an extremely low nucleotide diversity compared with the subfamily consensus sequence with an average age of 1.63 million years old. The young Alu insertions do not appear to accumulate preferentially on any individual human chromosome.