RESUMO
More than 10 megabases of contiguous genome sequence have been submitted to the databases by the Caenorhabditis elegans Genome Sequencing Consortium. To characterize the genes predicted from the sequence, we have developed high resolution FISH for visualization of mRNA distributions in whole animals. The high resolution and sensitivity afforded by the use of directly fluorescently labelled probes and confocal imaging permitted mRNA distributions to be recorded at the cellular and subcellular level. Expression patterns were obtained for 8 out of 10 genes in an initial test set of predicted gene sequences, indicating that FISH is an effective means of characterizing predicted genes in C. elegans.
Assuntos
Caenorhabditis/genética , Expressão Gênica , Genoma , Hibridização in Situ Fluorescente/métodos , Animais , Sequência de Bases , Caenorhabditis/citologia , Proteínas de Helminto/genética , Dados de Sequência Molecular , Proteínas Musculares/genética , RNA Mensageiro/análiseRESUMO
In constructing complete human chromosome maps, the relative order of markers and their precise chromosomal location will be combined. Multicolour in situ hybridisation, in which two probes are simultaneously hybridised to chromosomes and subsequently distinguished, potentially will provide both types of information. Using this technique, we have produced an ordered map of eight human chromosome 3 DNA markers, using small, single-copy probes that can detect target sequences ranging in size from 4 kb to as little as 500 bp.
Assuntos
Mapeamento Cromossômico/métodos , Cromossomos Humanos Par 3 , Cromossomos Humanos , Hibridização in Situ Fluorescente/métodos , Linfócitos/citologia , Células Cultivadas , Corantes Fluorescentes , Humanos , Indóis , Ativação Linfocitária , Linfócitos/imunologia , MetáfaseRESUMO
A method for in situ hybridization originally developed for mapping genes in the nematode, Caenorhabditis elegans has been adapted for high resolution cytological mapping of genes in the human. The probe DNAs are labelled by incorporation of biotin dUTP and the site of hybridization detected by immunofluorescence. For the accurate assignment of the hybridization signal to chromosome bands, visualized by staining with Hoechst 33258, a heterologous ribosomal DNA probe is also included in the hybridization reaction. These rDNA signals are used as fiducial markers when aligning the two fluorescent images. We demonstrate the method by assignment of the human thymocyte CD1 antigen genes to human chromosome 1q22-23.
Assuntos
Antígenos de Diferenciação de Linfócitos T/genética , Mapeamento Cromossômico , Cromossomos Humanos Par 1 , Sondas de DNA , Imunofluorescência , Humanos , Metáfase , Hibridização de Ácido NucleicoRESUMO
The nervous system of the nematode worm Ascaris contains about 250 nerve cells; of these, the motoneurons consist of five segmental sets, each containing 11 cells. Morphologically, the motoneurons can be divided into seven different types. Their geometry is simple: some are unbranched, others have one branch point, and the most complex have two. There is no neuropil in the nerve cords; synapses are made by axo-axonal contact or onto short spines. These features enable us to study the anatomy and physiology of the system with a degree of completeness that would be difficult in other systems. The physiological activity of five of the motoneurons has been investigated, three being excitatory and two inhibitory. The excitatory motoneurons receive input from intersegmental interneurons. The inhibitory motoneurons do not receive input from the interneurons; instead they receive their input from the excitatory motoneurons in a circuit that can mediate reciprocal inhibition between the dorsal and the ventral musculature.
