Topic
Exon
About: Exon is a research topic. Over the lifetime, 38308 publications have been published within this topic receiving 1745408 citations. The topic is also known as: exons.
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TL;DR: The gene encoding the precursor protein to the hormone oxytocin and its associated neurophysin has been isolated from a rat genomic library, and its sequence has been determined.
Abstract: The gene encoding the precursor protein to the hormone oxytocin and its associated neurophysin has been isolated from a rat genomic library, and its sequence has been determined. The small gene (approximately equal to 850 base pairs) predicts a mRNA of approximately equal to 500 bases [without the poly(A) tail]. The exon-intron organization is similar to that of the vasopressin gene, with two splice sites in the protein-coding region. The first exon (A) comprises the 5' noncoding promoter region, a putative signal peptide, the nonapeptide hormone oxytocin, and the NH2-terminal, variable region of neurophysin. The second exon (B) encodes the central, conserved region of neurophysin, and the third exon (C) encodes the remaining COOH terminus of neurophysin, with an additional arginine residue at its end, presumably cleaved off during post-translational processing. A stretch of 143 nucleotides within exon B, except for a single base change, is entirely homologous to the equivalent part of the rat vasopressin gene, offering support for a gene conversion event having recently affected the two genes.
410 citations
TL;DR: In this article, the authors proposed that a defective myosin-VIIA gene may also be responsible for deafness in Usher syndrome type I, USH1B, by linkage analysis of a single family whose members were affected with profound deafness, some of them presenting with vestibular dysfunction.
Abstract: Hereditary non-syndromic profound deafness affects about 1 in 2000 children prior to language acquisition. In 80% of the cases, the mode of transmission is autosomal recessive. The number of genes involved in these recessive forms of isolated deafness (DFNB genes) has been estimated to between 30 and 100. So far, ten DFNB genes have been mapped to human chromosomes, one of which has been isolated2. By linkage analysis of a single family whose members were affected with profound deafness, some of them presenting with vestibular dysfunction, DFNB2 has been mapped to chromosome 11q13 (ref. 3). The gene responsible for a form of Usher syndrome type I, USH1B, has been assigned to the same chromosomal region4. Usher syndrome associates profound congenital deafness and vestibular dysfunction with retinitis pigmentosa. In the homologous murine region are located the shaker-1 mutations responsible for deafness and vestibular dysfunction. It has been demonstrated that the murine shaker-1 and human USH1B phenotypes result from mutations in the gene encoding myosin-VIIA5,6. Based on mapping data as well as on the similarities between the phenotypes of DFNB2-affected patients and shaker-1 mouse mutants, we have proposed that a defective myosin-VIIA may also be responsible for DFNB2 (ref. 1). Sequence analysis of each of the coding exons of the myosin-VIIA gene (MYO7A) was thus undertaken in the DFNB2-affected family. In the last nucleotide of exon 15, a G to A transition was detected, a type of mutation that is known to decrease the efficiency of splicing7‐14. Accordingly, this result shows that different mutations in MYO7A result in either an isolated or a syndromic form of deafness.
410 citations
TL;DR: It is shown that rapid and transient transcriptional upregulation inherent to neuronal activation physiology creates U1 shortage relative to pre-mRNAs, and additional experiments suggest cotranscriptional PCPA counteracted by U1 association with nascent transcripts, a process the authors term telescripting, ensuring transcriptome integrity and regulating mRNA length.
410 citations
TL;DR: A novel, aberrant Rb protein detected in J82 bladder carcinoma cells was not able to form a complex with E1A and was less stable than p105-Rb, which was observed to result from a single point mutation within a splice acceptor sequence in J 82 genomic DNA.
Abstract: The retinoblastoma (Rb) antioncogene encodes a nuclear phosphoprotein, p105-Rb, that forms protein complexes with the adenovirus E1A and SV40 large T oncoproteins. A novel, aberrant Rb protein detected in J82 bladder carcinoma cells was not able to form a complex with E1A and was less stable than p105-Rb. By means of a rapid method for the detection of mutations in Rb mRNA, this defective Rb protein was observed to result from a single point mutation within a splice acceptor sequence in J82 genomic DNA. This mutation eliminates a single exon and 35 amino acids from its encoded protein product.
410 citations
TL;DR: Comparative nucleotide sequence analysis of a rearranged c-myc gene in a murine plasmacytoma and c-Myc cDNA from normal spleen reveals that chromosomal translocation in the plasmACYtoma breaks the c- myc gene within the first exon or intron.
Abstract: Comparative nucleotide sequence analysis of a rearranged c-myc gene in a murine plasmacytoma and c-myc cDNA from normal spleen reveals that chromosomal translocation in the plasmacytoma breaks the c-myc gene within the first exon or intron. In the plasmacytoma truncated c-myc RNAs initiate from newly exposed promoter sites. Nevertheless, the myc polypeptide produced in the plasmacytoma is probably the same as that from the intact c-myc gene because the exon lost by breakage and translocation is non-coding. The second and third exons of the mouse c-myc gene are substantially conserved in the v-myc gene of the avian retrovirus, MC29.
409 citations