Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Total poly(A)-containing RNA prepared from hen oviduct and centrifuged on an isokinetic sucrose gradient displays four peaks of optical absorbance. These have been identified by translation in vitro as lysozyme, ovomucoid, ovalbumin, and conalbumin mRNAs. Isolation and recentrifugation of the peaks results in partial purification of each mRNA. Molecular weights have been determined for the mRNAs on agarose gels containing 20 mM methylmercury hydroxide. Each mRNA possesses a number of apparently untranslated nucleotides ranging from approximately 900 bases for ovalbumin and conalbumin mRNAs to 200 bases for ovomucoid and lysozyme mRNAs. The mRNAs have been copied with avian myeloblastosis virus reverse transcriptase. Each mRNA with the exception of conalbumin gives rise to a high proportion of full length cDNA. Several parameters previously reported to influence the size distribution of cDNA had no effect on the length of cDNA made from any mRNA fraction. The proportion of full length copy does depend on the reverse transcriptase lot.
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PMID:Synthesis of full length cDNAs from four partially purified oviduct mRNAs. 63 80

In an earlier study we found that different forms of the v-myb oncogene transform myeloid cells which resemble either monoblasts [when v-myb of avian myeloblastosis virus (AMV) was used] or promyelocytes [when a point mutant in v-myb of AMV was used; Introna, M., Golay, J., Frampton J., Nakano, T., Ness, S.A. & Graf, T. (1990). Cell, 63, 1287-1297]. In the present study we have searched for genes expressed in AMV mutant-transformed promyelocytes that are not expressed in AMV-transformed monoblasts using a differential screening approach. Eight different genes were identified among more than 500 differentially expressed clones. The most abundant of these was the previously identified myb-regulated mim-1 gene. The others were found to encode a small calcium-binding (MRP-like) protein; the p20K protein; goose-type lysozyme; a ribonuclease A/angiogenin-related protein; and three non-identified proteins. Although these genes appear to be rather lineage restricted, their expression varied in different subtypes of transformed myelomonocytic cells, and only two of them (goose lysozyme and ribonuclease) showed a similar expression pattern in normal promyelocytes and macrophages, suggesting an aberrant gene regulation in the transformed cells. Co-transfection experiments of a reporter construct containing the promoter of the ribonuclease A-related gene indicated that this promoter is regulated by the v-Myb oncoprotein without the involvement of Myb-specific binding sequences.
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PMID:Identification of genes differentially expressed in two types of v-myb-transformed avian myelomonocytic cells. 154 65

The retroviral oncogene v-myb encodes a transcription factor (v-Myb) which is responsible for the transformation of myelomonocytic cells by avian myeloblastosis virus (AMV). v-Myb is thought to exert its biological effects by deregulating the expression of specific target genes. Here we have used DNaseI hypersensitive site mapping and reporter gene assays to study the activation of three Myb target genes--mim-1, the lysozyme gene and the C/EBPbeta gene--all of which are activated by Myb in myelomonocytic cells but not in other hematopoietic lineages. We have found that these genes are activated by Myb via more than one cis-regulatory region. Our data suggest that all three genes are activated by Myb by dual mechanisms involving the promoters as well as enhancers. Using a cell line that expresses an estrogen-inducible v-Myb/estrogen receptor fusion protein we have also determined the effect of Myb on the expression of the C/EBPalpha gene. Our results show that C/EBPalpha expression is down-regulated by v-Myb. Thus, v-Myb affects the expression of two C/EBP family members in opposite directions.
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PMID:A dual activation mechanism for Myb-responsive genes in myelomonocytic cells. 1795 8

The oncoprotein v-Myb of avian myeloblastosis virus (AMV) transforms myelomonocytic cells by deregulating specific target genes. Previous work has shown that the oncogenic potential of v-Myb was activated by truncation of N- and C-terminal sequences of c-Myb and was further increased by amino acid substitutions in the DNA-binding domain and other parts of the protein. We have analyzed the activation of the chicken lysozyme gene which is strongly activated by c-Myb but not by its oncogenic counterpart v-Myb. We report that Myb acts on two different cis-regulatory elements, the promoter and an enhancer located upstream of the gene. Interestingly, the activation of the enhancer was abolished by the oncogenic amino acid substitutions. We demonstrated that a single Myb-binding site is responsible for the activation of the lysozyme enhancer by Myb and showed that the v-Myb protein of AMV was unable to bind to this site. Our data demonstrate for the first time that oncogenic activation of Myb alters its DNA-binding specificity at a physiological Myb target gene.
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PMID:Oncogenic point mutations in the Myb DNA-binding domain alter the DNA-binding properties of Myb at a physiological target gene. 1795 53