Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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alpha 2u-Globulin is a rat protein of as yet unknown function whose synthesis can be induced by glucocorticoids and several other hormones. Induction by glucocorticoids is a secondary response to the hormone: protein synthesis is required before the hormone can exert its stimulatory effect on alpha 2u-globulin transcription. We have used the linker-scanning mutagenesis procedure, followed by transfer of the mutant genes into mouse L-cells for analysis of their phenotype, to determine sequences within a cloned alpha 2u-globulin promoter that are required for its regulation by glucocorticoids. Mutations between positions -115 and -160 abolish or greatly reduce the inducibility of alpha 2u-globulin by the hormone. Mutations just upstream from this region, between positions -177 and -220, have an opposite effect; they increase induction two- to fourfold.
Mol Cell Biol 1986 Jul
PMID:Nucleotide sequences required for the regulation of a rat alpha 2u-globulin gene by glucocorticoids. 243 Dec 90

High affinity binding of guanine nucleotides and the ability to hydrolyze bound GTP to GDP are characteristics of an extended family of intracellular proteins. Subsets of this family include cytosolic initiation and elongation factors involved in protein synthesis, and cytoskeletal proteins such as tubulin (Hughes, S.M. (1983) FEBS Lett. 164, 1-8). A distinct subset of guanine nucleotide binding proteins is membrane-associated; members of this subset include the ras gene products (Ellis, R.W. et al. (1981) Nature 292, 506-511) and the heterotrimeric G-proteins (also termed N-proteins) (Gilman, A.G. (1984) Cell 36, 577-579). Substantial evidence indicates that G-proteins act as signal transducers by coupling receptors (R) to effectors (E). A similar function has been suggested but not proven for the ras gene products. Known G-proteins include Gs and Gi, the G-proteins associated with stimulation and inhibition, respectively, of adenylate cyclase; transducin (TD), the G-protein coupling rhodopsin to cGMP phosphodiesterase in rod photoreceptors (Bitensky, M.W. et al. (1981) Curr. Top. Membr. Transp. 15, 237-271; Stryer, L. (1986) Annu. Rev. Neurosci. 9, 87-119), and Go, a G-protein of unknown function that is highly abundant in brain (Sternweis, P.C. and Robishaw, J.D. (1984) J. Biol. Chem. 259, 13806-13813; Neer, E.J. et al. (1984) J. Biol. Chem. 259, 14222-14229). G-proteins also participate in other signal transduction pathways, notably that involving phosphoinositide breakdown. In this review, I highlight recent progress in our understanding of the structure, function, and diversity of G-proteins.
Mol Cell Endocrinol 1987 Jan
PMID:Signal transduction by guanine nucleotide binding proteins. 243 86

The mitochondrial respiratory system is absent in slender bloodstream forms of Trypanosoma brucei, incomplete in stumpy bloodstream forms, and complete in procyclic (insect) forms. The steady-state abundance of transcripts of some mitochondrially encoded components of the respiratory system correlates with its differential expression in different life cycle stages. Recently, it was reported that uridines which are not encoded in the genome are added to cytochrome b and cytochrome oxidase II transcripts. We now report that the (U)+ transcripts of both genes are found in procyclic forms and to some degree in stumpy forms but are absent in slender forms. The uridine additions to cytochrome oxidase II correct a frameshift in the gene and presumably allow production of a full-length protein, whereas those added to cytochrome b create an in-frame AUG which extends the N terminus of the predicted protein by 20 amino acids. The stage specificity of uridine additions to these transcripts thus reflects the life cycle stage during which the protein products would be used. Transcripts of MURF2, a gene of unknown function, have additional uridines in both slender and procyclic forms which create two in-frame AUGs. MURF2 transcripts additionally differ from the DNA sequence in ways which cannot be explained by uridine addition alone, implying that other processes alter these transcripts.
Mol Cell Biol 1988 Mar
PMID:Developmental aspects of uridine addition within mitochondrial transcripts of Trypanosoma brucei. 245 74

Cloned cDNAs encoding the precursor protein for motilin and a novel peptide, motilin-associated peptide, were isolated from a library derived from porcine intestinal mucosa mRNA. Nucleotide sequence analysis predicts a precursor protein of 119 amino acids including a signal peptide in direct linkage with the 22 amino acid sequence for motilin, and a 70 amino acid peptide of unknown function. The putative bioactive moieties are separated by Lys-Lys, dibasic residues that serve as substrates for cleavage by proteolytic maturation enzymes in many polyprotein precursors. While there is an abundant literature detailing a spectrum of tissues and cell types which express motilin like immunoreactivity, analysis of mRNA derived from many of these tissues suggests that the mRNA for the mucosal motilin precursor is only transcribed in this tissue. The nature of the immunoreactive material in the central nervous system and other peripheral tissues remains to be determined.
Mol Endocrinol 1988 Feb
PMID:Characterization of complementary deoxyribonucleic acid for precursor of porcine motilin. 245 53

The trmD operon of Escherichia coli encodes the ribosomal proteins S16 and L19, the tRNA(m1G37)methyltransferase and a 21,000 Mr protein of unknown function. Here we demonstrate that, in contrast to the expression of other ribosomal protein operons, the amount of trmD operon mRNA and the rate of synthesis of the proteins encoded by the operon respond to increased gene dosage. The steady-state level of the mRNA was about 18 times higher, and the relative rate of synthesis of the ribosomal proteins S16 and L19, the tRNA(m1G37)methyltransferase and the 21,000 Mr protein was 15, 9, 25 and 23 times higher, respectively, in plasmid-containing cells than in plasmid-free cells. Overproduced tRNA(m1G37)methyltransferase and 21,000 Mr protein were as stable as E. coli total protein, whereas the two ribosomal proteins were degraded to a large extent. The steady-state amount of S16 and L19 in the plasmid-containing cells exceeded that in plasmid-free cells by threefold and twofold, respectively. No significant effect on the synthesis of the trmD operon proteins from the chromosomally located genes was observed when parts of the operon were expressed on different plasmids. Taken together, these results suggest that the expression of the trmD operon is not subject to transcriptional or translational feedback regulation, and demonstrate that not all ribosomal protein operons are regulated in the same manner. We propose that ribosomal protein operons that do not encode proteins that bind directly to rRNA are not under autogenous control. Metabolic regulation at the transcriptional level and protein degradation are plausible mechanisms for the control of expression of such operons.
J Mol Biol 1988 Sep 05
PMID:Non-autogenous control of ribosomal protein synthesis from the trmD operon in Escherichia coli. 246 Jun 31

Entamoeba histolytica kills cells by contact dependent cytolysis. The mechanism underlying this process must be of rapid onset because target cells round up and show marked zeiosis within 15 min of contact. In earlier work, we identified a remarkable ion-channel forming protein which we named amoebapore, that may contribute to the amoeba-induced target cell killing. Within the amoeba it exists as part of a supramolecular aggregate together with other proteins of unknown function. In this work we report the purification of a solubilized form of the amoebapore. Amoebapore was found to exist as an apparent dimer of the previously reported protein whose molecular weight had been determined under denaturing conditions. Two isoforms of this dimer, with pI values of 6.8 and 5.3 present at a ratio of 7 to 1, were identified and purified. Both isoforms demonstrate ion-channel forming activity in planar lipid membranes. These channels show a unit conductance of 5-20 pS and remain open for less than 1 s. Upon lateral aggregation, opening becomes concerted to a greater degree with channel conductance are observed. The isolated particulate form of amoebapore depolarizes cells.
Mol Biochem Parasitol 1989 Mar 15
PMID:Isolation, characterization and partial purification of a transferable membrane channel (amoebapore) produced by Entamoeba histolytica. 246 84

The chromosomal DNA fragments of Escherichia coli K-12 were cloned into a mini-F cosmid, pRE435, after partial digestion with restriction endonuclease Sau3AI. The clones were first screened for PyrC+ and then for other genes, including rpmF encoding ribosomal protein L32 that had been mapped near pyrC (I. Janda, M. Kitakawa, and K. Isono, Mol. Gen. Genet. 201:443-436, 1985). Thus, we obtained a total of five rpmF-containing clones. The rpmF gene was located on the chromosomal segment in one of the clones (pAY2-5) by insertional mutagenesis with transposon gamma delta, followed by analysis of the gene products by the maxicell method. Hybridization analysis of clone pAY2-5 with the ordered clone bank (Y. Kohara, K. Akiyama, and K. Isono, Cell 50:495-508, 1987) indicates that a gap at the 1,510-kilobase coordinates in the physical map of E. coli can be bridged by this clone. The nucleotide sequence of the region containing rpmF was accordingly established. In addition, the RNA transcripts from the chromosomal region containing rpmF were analyzed, and the transcriptional initiation sites were determined. The results suggest that rpmF forms an operon with the gene termed g30k which codes for a 30-kilodalton protein of unknown function. At least four transcripts were found to code for ribosomal protein L32.
 ...
PMID:Cloning and analysis of an Escherichia coli operon containing the rpmF gene for ribosomal protein L32 and the gene for a 30-kilodalton protein. 247 62

The trmD operon is a four-cistron operon in which the first and fourth genes encode ribosomal proteins S16 (rpsP) and L19 (rplS), respectively. The second gene encodes a 21,000 Mr polypeptide of unknown function and the third gene (trmD) encodes the enzyme tRNA(m1G37)methyltransferase, which catalyzes the formation of 1-methylguanosine (m1G) next to the 3' end of the anticodon (position 37) of some tRNAs in Escherichia coli. Here we show under all regulatory conditions studied, transcription initiates at one unique site, and the entire operon is transcribed into one polycistronic mRNA. Between the promoter and the first gene, rpsP, an attenuator-like structure is found (delta G = -18 kcal; 1 cal = 4.184 J), followed by four uridine residues. This structure is functional in vitro, and terminates more than two-thirds of the transcripts. The different parts of the trmD operon mRNA decay at a uniform rate. The stability of the trmD mRNA is not reduced with decreasing growth rate, which is in contrast to what has been found for other ribosomal protein mRNAs. Furthermore, earlier experiments have shown the existence of differential expression as well as non-co-ordinate regulation within the operon. Our results are consistent with the regulation of the trmD operon being due to some mechanism(s) operating at the post-transcriptional level, and do not involve differential degradation of different mRNA segments, internal promoters or internal terminators.
J Mol Biol 1989 Aug 20
PMID:Differentially expressed trmD ribosomal protein operon of Escherichia coli is transcribed as a single polycistronic mRNA species. 247 11

STA1 encodes a secreted glucoamylase of the yeast Saccharomyces cerevisiae var. diastaticus. Glucoamylase secretion is controlled by the mating type locus MAT; a and alpha haploid yeast cells secrete high levels of the enzyme, but a/alpha diploid cells produce undetectable amounts. It has been suggested that STA1 is regulated by MATa2 (I. Yamashita, Y. Takano, and S. Fukui, J. Bacteriol. 164:769-773, 1985), which is a MAT transcript of previously unknown function. In contrast, this work shows that deletion of the entire MATa2 gene had no effect on STA1 regulation but that deletion of MATa1 sequences completely abolished mating-type control. In all cases, glucoamylase activity levels reflected STA1 mRNA levels. It appears that STA1 is a haploid-specific gene that is regulated by MATa1 and a product of the MAT alpha locus and that this regulation occurs at the level of RNA accumulation. STA1 expression was also shown to be glucose repressible. STA1 mRNA was induced in diploids during sporulation along with SGA, a closely linked gene that encodes an intracellular sporulation-specific glucoamylase of S. cerevisiae. A diploid strain with a MATa1 deletion showed normal induction of STA1 in sporulation medium, but SGA expression was abolished. Therefore, these two homologous and closely linked glucoamylase genes are induced by different mechanisms during sporulation. STA1 induction may be a response to the starvation conditions necessary for sporulation, while SGA induction is governed by the pathway by which MAT regulates sporulation. The strain containing a complete deletion of MATa2 grew, mated, and sporulated normally.
Mol Cell Biol 1989 Sep
PMID:Regulation of STA1 gene expression by MAT during the life cycle of Saccharomyces cerevisiae. 250 39

The trmD operon of Escherichia coli consists of the genes for the ribosomal protein (r-protein) S16, a 21 kDa protein (21K) of unknown function, the tRNA(m1G37)methyltransferase (TrmD), and r-protein L19, in this order. Previously we have shown that the steady-state amount of the two r-proteins exceeds that of the 21K and TrmD proteins 12- and 40-fold, respectively, and that this differential expression is solely explained by translational regulation. Here we have constructed translational gene fusions of the trmD operon and lacZ. The expression of a lacZ fusion containing the first 18 codons of the 21K protein gene is 15-fold higher than the expression of fusions containing 49 or 72 codons of the gene. This suggests that sequences between the 18th and the 49th codon may act as a negative element controlling the expression of the 21K protein gene. Evidence is presented which demonstrates that this regulation is achieved by reducing the efficiency of translation.
Mol Gen Genet 1989 Nov
PMID:A regulatory element within a gene of a ribosomal protein operon of Escherichia coli negatively controls expression by decreasing the translational efficiency. 251 39


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