RESUMO
Two main transcripts of the s-rex/NSP gene are generated by different promoter usage and differential splicing in neuronal and endocrine tissues of higher vertebrates, suggesting that the encoded proteins function in neuroendocrine secretion. To know more about the structure, expression and evolution of this new gene, we have cloned full-length cDNAs for both 1.5 kb and 3.5 kb transcripts from rat and chicken brain cDNA libraries. Sequence analysis has revealed structures within the 3'-UTR that are conserved in these mRNAs and human NSP mRNA and that could be involved in specific compartmentalization of s-rex/NSP mRNA in neuronal cells. An additional transcript generated by differential splicing of internal exons has been cloned from a rat DRG library. Low levels of s-rex/NSP mRNAs have been detected in some non-neuroendocrine tissues, although substantial levels of a unique transcript have been found in rat tests. By RT-PCR analysis, other tissue-specific transcripts that are products of rare splicing events have been revealed.
Assuntos
Processamento Alternativo , Proteínas do Tecido Nervoso/genética , RNA Mensageiro/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Galinhas , Clonagem Molecular , DNA Complementar , Éxons , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas , Ratos , Distribuição TecidualRESUMO
The d4 domain, a novel zinc finger-like structural motif, was first revealed in the rat neuro-d4 protein. Here we demonstrate that the d4 domain is conserved in evolution and that three related genes form a d4 family in the human genome. The human neuro-d4 is very similar to rat neuro-d4 at both the amino acid and the nucleotide levels. Moreover, the same splice variants have been detected among rat and human neuro-d4 transcripts. This gene has been localized on chromosome 19, and two other genes, members of the d4 family isolated by screening of the human genomic library at low stringency, have been mapped to chromosomes 11 and 14. The gene on chromosome 11 is the homolog of the ubiquitously expressed mouse gene ubi-d4/requiem, which is required for cell death after deprivation of trophic factors. A gene with a conserved d4 domain has been found in the genome of the nematode Caenorhabditis elegans. The conservation of d4 proteins from nematodes to vertebrates suggests that they have a general importance, but a diversity of d4 proteins expressed in vertebrate nervous systems suggests that some family members have special functions.
Assuntos
Genoma Humano , Família Multigênica/genética , Proteínas do Tecido Nervoso/genética , Fatores de Transcrição , Dedos de Zinco/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Mapeamento Cromossômico , Cromossomos Humanos Par 19/genética , Sequência Conservada , Éxons/genética , Humanos , Dados de Sequência Molecular , Splicing de RNA , Ratos , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido NucleicoRESUMO
To isolate genes differentially expressed in the rat brain cortex and cerebellum, a subtractive cDNA cloning procedure requiring only small quantities of poly(A+) RNA, followed by differential screening, was used. Two novel genes, MK and 3L7, with cortex- and cerebellum-specific expression were identified. These genes displayed different expression patterns in the brain cortex, cerebellum, and hippocampus during postnatal development.
Assuntos
Cerebelo/metabolismo , Córtex Cerebral/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Animais , Clonagem Molecular , DNA Complementar , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos WistarRESUMO
To identify genes differentially expressed in the developing rat cerebellum, a subtractive cDNA cloning procedure, followed by differential screening, was used. Four novel genes, MB, MF, 3E7, and 3C6, the transcriptional activity of which changed by a factor of five during cerebellar development, were isolated. The genes obtained were differentially expressed in different regions of the central nervous system. Variations in the levels of corresponding transcripts in the brain cortex and cerebellum were also recorded during postnatal rat development.
Assuntos
Cerebelo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Animais , Cerebelo/crescimento & desenvolvimento , Clonagem Molecular , DNA Complementar , Hibridização de Ácido Nucleico , Ratos , Ratos WistarRESUMO
Using a subtractive hybridization technique directed to cloning transcripts with compartmentalized distributions within cerebral cortex neurons, we have isolated rat s-rex mRNAs that are analogues of the human neuroendocrine-specific NSP gene transcripts. Differential splicing produces two main s-rex mRNA that have different regional distributions in the developing and mature rat nervous system. In certain populations of adult brain neurons, most of s-rexs, mRNA and a substantial amount of s-rexb mRNA are localized to the axonal pole of the cell body. The localization of S-Rex/NSP proteins in these neurons suggests that s-rex mRNA compartmentalization targets the encoded proteins to specific regions of the neuron.
