RESUMO
By sequencing 11,405 individual expressed sequence tags (ESTs) from a cDNA library of a human skeletal muscle, we identified 1945 individual transcripts, 725 of which showed no correspondence with known human genes. We report here the chromosomal localization of 267 of these, obtained by radiation hybrid (RH) mapping. The map position of additional 242 ESTs from the same library, corresponding to known human genes, is also reported. The resulting information provides a preliminary genomic transcriptional profile of a human muscle. Several genes occur in clusters on different chromosomes. Moreover, chromosomes 17, 19, 21 and X appear to be significantly rich in muscle ESTs. By analysing several collections of ESTs from different tissues, we observed significant deviations in the distribution of ESTs by chromosome in fetal heart, adult brain and adult retina, supporting the hypothesis that a non-random localization of genes expressed in specific tissues might not be uncommon. The selective concentration of expressed genes in some chromosomes and in specific chromosomal subregions in a given tissue might reflect the existence of batteries of genes under the same control mechanisms, regulating tissue-specific gene expression.
Assuntos
Mapeamento Cromossômico , DNA Complementar/análise , Músculo Esquelético , RNA Mensageiro/análise , DNA Complementar/genética , Bases de Dados como Assunto , Regulação da Expressão Gênica , Biblioteca Gênica , Humanos , Reação em Cadeia da Polimerase , RNA Mensageiro/metabolismo , Transcrição GênicaRESUMO
The chromosome assignment of 115 expressed sequence tags (ESTs) from human skeletal muscle, 101 of which identify unknown human genes, is reported. The ESTs were selected among over 4,000 obtained from systematic sequencing of a skeletal muscle cDNA library containing 3' portions of the mRNAs. Chromosome assignments were obtained by PCR amplification of two panels of human x rodent somatic cell hybrids. Analysis of these preliminary data suggests a nonrandom distribution of muscle ESTs in the human chromosome complement. The unexpected occurrence of multiple chromosome localizations for some ESTs is discussed.
Assuntos
Mapeamento Cromossômico , DNA Complementar , Músculo Esquelético/metabolismo , Adulto , Animais , Linhagem Celular , Cromossomos , Feminino , Expressão Gênica , Biblioteca Genômica , Humanos , Células Híbridas , RoedoresRESUMO
Members of the ICE/CED-3 protease family appear to play an essential role in programmed cell death process. In this paper the chromosomal localization of the human genes CPP32, Mch2, Mch3 and Ich-1 is reported, obtained by Radiation Hybrid Mapping. CPP32 was assigned to chromosome 4q33-q35.1, Mch2 to chromosome 4q25-q26, Mch3 to chromosome 10q25.1-q25.2 and Ich-1 to chromosome 7q35. Ich-1 was found to map very close to the marker WI-9353. The possible overlapping of the two independent locus assignments is considered. The genomic distribution of these genes is discussed, with particular reference to the co-location with some human genetic diseases all characterized by autosomal dominant inheritance and by similar malformative features.
Assuntos
Apoptose/genética , Caspases , Mapeamento Cromossômico , Cromossomos Humanos/genética , Cisteína Endopeptidases/genética , Animais , Sequência de Bases , Caspase 2 , Caspase 3 , Caspase 6 , Cromossomos Humanos Par 10/genética , Cromossomos Humanos Par 4/genética , Cromossomos Humanos Par 7/genética , Anormalidades Congênitas/genética , Cricetinae , Primers do DNA/genética , Humanos , Células Híbridas , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Proteínas/genéticaRESUMO
A systematic study on the mRNA species expressed in the human skeletal muscle is presented in this paper. To carry on this study, a new method has been developed for the construction of unbiased cDNA libraries specially designed for the production of ESTs corresponding to the 3'-end portion of the mRNAs. The method has been applied to human skeletal muscle, where the analysis of the transcription profile is particularly difficult for the presence of several very abundant transcripts. To detect and quantify high-level mRNAs, the first 1054 ESTs were obtained from randomly selected clones. The 10 most abundant transcripts accounted for > 45% of the clones. Subsequently, these transcripts were identified by filter hybridization, thus making DNA sequencing more productive. Overall, 4370 clones were identified: 3372 by DNA sequencing and 998 by filter hybridization. The number of groups of sequences identifying individual transcripts was relatively low compared with other tissues, resulting in a total of 934 groups out of 4370 ESTs. Of these, 719 groups were represented by only one sequence.