Differential Gene Transcription Research Articles

Differential Transcription and Translation of Immediate Early Genes in the Gerbil Hippocampus after Transient Global Ischemia

Excitotoxic activation of glutamate receptors is thought to be a key event for the molecular pathogenesis of postischemic delayed neuronal death of CA-1 neurons in the gerbil hippocampus. Glutamate receptor stimulation also causes induction of transcription factors that belong to the class of immediate early genes. We examined the expression of six different immediate early genes in the gerbil hippocampus after transient global ischemia. Comparative analysis of c-fos and Krox-24 expression was carried out in the same animals at the transcriptional and translational level by in situ hybridization and immunocytochemistry. Postischemic synthesis of four additional immediate early gene (IEG)-encoded proteins (FOS-B, c-JUN, JUN-B, and JUN-D) was investigated by immunocytochemistry at recirculation intervals between 1 and 48 h. After 5 min of ischemia, transcription of c-fos and Krox-24 mRNA was induced in all hippocampal subpopulations with peak expression at 1 h after recirculation. In vulnerable CA-1 neurons, increased transcription of c-fos and Krox-24 was not followed by translation into protein. Induction of immediate early gene-encoded proteins was restricted to neuronal populations less vulnerable to brief ischemia and identified neurons that are targets of glutamate receptor-mediated neurotoxicity but that are destined to survive. Our data indicate an asynchronous synthesis and persistence of individual IEG-encoded proteins in these neurons. The staggered induction implies that combinatorial changes of transcription factors allow a differential postischemic regulation of target gene expression both spatially and over time.

Selective protein degradation in the yeast exocytic pathway.

Protein degradation in the exocytic pathway was studied in Saccharomyces cerevisiae using human alpha-1-protease inhibitor (A1Pi) as a reporter molecule. Yeast cells transformed with A1Pi cDNA genes synthesized A1Pi that entered the secretion pathway and accumulated in the endoplasmic reticulum (ER). Cells expressing A1PiM (wild-type) accumulated about 10-fold more A1Pi than cells expressing A1PiZ (secretion defective variant). Analyses of A1Pi mRNA indicated that the low level of A1PiZ relative to A1PiM was not the result of differential gene transcription. Pulse-chase A1Pi radiolabeling showed that A1PiM and A1PiZ were degraded at different rates and suggested a rapid specific turnover of newly synthesized A1PiZ in the ER. Accumulated A1Pi was degraded at comparable rates in both wild-type cells and cells deficient in vacuolar protease activity, indicating that degradation of A1Pi did not occur in the vacuole. Studies to investigate the intracellular location of the degradative process, using temperature-sensitive secretion defective yeast strains, suggested the possibility that degradation occurs not only in the ER but at a second site accessed by vesicle transport. Together, these results demonstrate that a selective protein degradation process operates early in the yeast cell exocytic pathway.

Probing Functional Organization within the Nucleus: Is Genome Structure Integrated with RNA Metabolism?

The cell nucleus is remarkable in the complexity of critical functions it must perform, and yet this complexity contrasts sharply with the simplified view of the nuclear interior that has persisted for many years. The nucleus is involved in essentially all aspects of cell function and is directly responsible for such intricate tasks as genome packaging, DNA replication, differential gene transcription, RNA processing, selective RNA transport, and cell division. In recent years, great advances have been made in understanding the biochemistry of many nuclear functions; however, we have just begun to discover how these processes are integrated into nuclear structure. Perhaps the nuclear interior has largely escaped our detailed scrutiny because of the enormous density of its content. Electron microscopic observations have provided evidence for internal structures (for review, see Fakan and Puvion 1980; see below), but the functional significance of much of this structure remains poorly understood. The genome...

Differential transcription of Pgk genes during spermatogenesis in the mouse

We have analyzed the occurrence of transcripts produced from the ubiquitously expressed, X-linked Pgk-1 gene and the testis-specific, autosomal Pgk-2 gene during spermatogenesis in the mouse. We found that tissue specificity, developmental specificity, and cell-type specificity of these mRNAs parallel that previously reported for the two protein isozymes of phosphoglycerate kinase (PGK) encoded by these two genes. This indicates that primary regulation of differential expression of the Pgk genes during spermatogenesis is exerted at the transcriptional level. We first detected Pgk-2 mRNA in preleptotene spermatocytes, indicating that transcription of Pgk-2 is initiated coincident with the onset of meiosis in male germ cells, and then continues to increase in later spermatocytes and postmeiotic round spermatids. This expression initiates prior to an initial decline in Pgk-1 transcript levels observed in pachytene spermatocytes, which apparently follows inactivation of the single X chromosome in spermatogenic cells. However, unlike cessation of Pgk-1 transcription from the inactivated X chromosome in female somatic cells, we show that inactivation of the Pgk-1 locus in spermatogenic cells is not followed by methylation of a key CpG dinucleotide in the promoter region. These results support the idea that specific expression of the Pgk-2 gene in meiotic and postmeiotic spermatogenic cells has evolved to compensate for reduced levels of Pgk-1 gene product caused by transient X-chromosome inactivation in these cells. They further suggest that reinitiation of transcription of the paternal Pgk-1 allele shortly after fertilization is facilitated by constitutive hypomethylation in the promoter region of this gene throughout spermatogenesis.

Current concepts in embryonic craniofacial development.

Embryology mirrors phylogeny. The phenotypic expression of the genome is the result of differential gene transcription, the critically timed turning on and off of specific genes by transcription factors to produce cyto-, histo-, and morpho-differentiation that fleetingly reflects evolutionary stages of development during ontogeny. Hox genes regulate transcription of other structural genes and are responsible for patterning of the facial primordia. Cephalic development involves extremely complex morphogenetic mechanisms built on conserved elements that have undergone enormous evolutionary changes. Transient expression of phylogenetic origins characterize ontogeny and are reflected in defective development that may be due to inappropriate expression of Hox genes or distorted or disrupted epignetic processes. The mechanisms by which genetic information is transformed into morphological patterning by the actions of growth factors, morphogenes, and receptors are currently being identified. Biochemical, immunological, and allometric analyses of embryos and fetuses in experimental and descriptive studies are elucidating details of units of craniofacial morphogenesis--faciogenesis, palatogenesis, gnathogenesis, odontogenesis. Three-dimensional model computer-assisted reconstruction of sectioned embryos and fetuses provides a further technique for understanding the complex configurations of tissue migratory patterns and growth sites that account for normal and abnormal craniofaciogenesis.

Growth conditions mediate differential transcription of fim genes involved in phase variation of type 1 pili.

Type 1 pili in Escherichia coli undergo phase variation in which individual cells in a population reversibly switch between piliated (Pil+) and nonpiliated (Pil-) states. The switching process is mediated by an invertible DNA fragment which contains the promoter for fimA, the gene encoding the major structural subunit of type 1 pili. Although type 1 pili randomly phase vary in broth cultures, many clinical isolates of E. coli do not express type 1 pili when cultured on agar media. We investigated the role of the invertible element and the upstream genes, fimB and fimE, in the agar-mediated suppression of pili in an agar-negative clinical isolate, strain 149. Southern hybridization and polymerase chain reaction analyses of the fimA promoter region in broth-grown 149 cells indicated that the invertible element was present in orientations corresponding to both Pil+ and Pil- phenotypes. In contrast, only one orientation of the invertible element, corresponding to the Pil- phenotype, was observed in strain 149 cells cultured on agar. A second clinical isolate, strain 2-7, which expresses type 1 pili on agar was also examined; the invertible element was found in both the Pil+ and Pil- orientations during growth of this strain on agar as well as in broth. The introduction of the fim gene cluster from strain J96 on a multicopy plasmid into agar-negative strain 149 resulted in the production of both J96 and 149 pili during growth on agar. Experiments with subclones of the J96 genes indicated that the presence of an intact fimB gene allowed strain 149 pili to be produced on agar. Differences in pilus production between agar and broth cultures appear to be the result of differential transcription of fimB and fimE under the two growth conditions. In contrast, the pattern of expression of these genes in agar phase-variable strain 2-7 did not differ between broth- and agar-grown cells.

Developmental and organ-specific changes in promoter DNA-protein interactions in the tomato rbcS gene family.

The five genes encoding ribulose-1,5-bisphosphate carboxylase (rbcS) from tomato are differentially expressed. Transcription of the genes is organ specific and developmentally regulated in fruit and light regulated in cotyledons and leaves. DNase I footprinting assays were used to map multiple sites of DNA-protein interaction in the promoter regions of all five genes and to determine whether the differential transcriptional activity of each gene correlated with developmental or organ-specific changes in DNA-protein interactions. We show organ-specific differences in DNase I protection patterns, suggesting that differential transcription of rbcS genes is controlled at least in part at the level of DNA-protein interactions. In contrast, no changes were detected in the DNase I footprint pattern generated with nuclear extracts from dark-grown cotyledons versus cotyledons exposed to light, implying that light-dependent regulation of rbcS transcription is controlled by protein-protein interactions or modification of DNA binding proteins. During development of tomato fruit, most DNA-protein interactions in the rbcS promoter regions disappear, coincident with the transcriptional inactivation of the rbcS genes. In nuclear extracts from nonphotosynthetic roots and red fruit, the only detectable DNase I protection corresponds to a G-box binding activity. Detection of other DNA binding proteins in extracts from these organs and expression of nonphotosynthetic genes exclude the possibility that roots and red fruit are transcriptionally inactive. The absence of complex promoter protection patterns in these organs suggests either that cooperative interactions between different DNA binding proteins are necessary to form functional transcription complexes or that there is developmental and organ-specific regulation of several rbcS-specific transcription factors in these organs. The DNase I-protected DNA sequences defined in this study are discussed in the context of conserved DNA sequence motifs and previously characterized binding sites.

Synthesis of tubulin during early postgastrula development of Artemia: Isotubulin generation and translational regulation

Isotubulin diversity and the synthesis of tubulin were examined during development of the brine shrimp, Artemia. It was found, by Northern and dot-blot analyses, that Artemia possess constant amounts of one size class of mRNA each for α- and β-tubulin during the first 24 hr of postgastrula development. Two-dimensional gel electrophoresis and fluorography, following the in vitro translation of developmentally staged poly(A) + mRNA, yielded one α- and one β-tubulin. Clearly, the isotubulin diversity seen on Coomassie blue-stained two-dimensional gels of Artemia tubulin is not generated by differential gene transcription during postgastrula growth, nor is development accompanied by synthesis of novel isotubulins resolvable by the methods employed. Characterization of polysomal poly(A) + mRNA, and of proteins synthesized in vivo, indicated very little tubulin was synthesized in Artemia as they developed from gastrula to first instar larvae. The results suggest control of tubulin synthesis in Artemia by a mechanism that restricts binding of the message to ribosomes. Of general significance, it appears that a complex metazoan animal is able to undergo extensive growth with limited tubulin synthesis and in the absence of differential expression of tubulin genes. Moreover, the capacity of microtubules to assume changing and/or increased functions associated with cellular development is seemingly not dependent on the synthesis of new tubulin isoforms.

Functional tagging of regulatory elements in the plant genome

In comparison with animals, relatively few plant genes have been identified that have been shown to be under organ-, tissue- or cell-type-specific regulation. In this paper, we describe how the beta-glucuronidase (GUS) reporter gene (gusA or uidA), fused to a weak promoter (a truncated (-90 bp) CaMV35S promoter), can be used to identify tissue-specific markers in transgenic tobacco plants. The rationale was that the expression of gusA would be determined primarily by position effect. Quantitative analysis revealed that, of 184 -90-gus transgenic plants, 73% exhibited gusA gene activation in leaf tissue, and the level of GUS enzyme activity varied over a 300-fold range within the population. In comparison, transformation with a promoterless gusA gene resulted in GUS expression in 78% of all plants analyzed (in leaf and/or root) and expression levels were three-fold or more lower. Qualitative GUS analysis of single locus -90-gus transformants revealed differential expression in diverse tissues. The spatial pattern of GUS activity was unique to individual transformants, was a reflection of differential gusA gene transcription, and was stably transmissible to progeny. Evidence for preferential expression in roots not only of the -90-gus, but also the promoterless gusA gene is presented. The value of the -90 bp promoter-gusA sequence, which is termed an 'interposon', as a tool both to identify native enhancer sequences in situ and to investigate position effects in plants, is discussed.

Differential Transcription of the Fibroin and Sericin-1 Genes in Cell-Free Extracts1 : (fibroin gene/sericin gene/differential transcription/nuclear extracts/Bombyx mori).

Devices of the extraction procedues and a recovery of the final supernatant as tiers accompanied with a transcription ability assessment of the individual tiers have enabled us to develop a variety of cell-free transcription systems. The latter step revealed that the factors necessary for faithful transcription as well as enhanced transcription form aggregates or complexes indicating an intrinsic nature of these factors to interact each other. Altogether 14 cell-free transcription systems have been developed from Bombyx mori embryos and tissues of various developmental stages and a cultured cell line, and screened for activities enhancing the basal promoter levels of the silk genes. Using these extracts a differential transcription of plural tissue-specific genes was tried. The fibroin gene was preferentially transcribed than the sericin-1 gene in the extracts from the posterior silk glands where the fibroin gene is specifically transcribed in vivo, while the sericin-1 gene was dominant to the fibroin gene in the extracts from the middle silk glands where the sericin-1 gene is specifically transcribed. Thus, these nuclear extracts offer us a biochemical clue assaying factors responsible for the differential transcription.

Induction of P-450IIB genes within the rat liver acinus is not dependent on the chemical inducer or on the acinar organization

P-450IIB genes (P-450b and P-450e in rat) are induced following treatment with phenobarbital predominantly in hepatocytes located in zones 2 and 3 of the liver acinus. The previous finding of phenobarbital-mediated induction of P-450IIB mRNAs and apoproteins in the same zonal hepatocytes suggests that this differential induction is most likely due to zonal differences in the activation of gene transcription. To determine whether differential P-450IIB gene transcription was dependent on the type of inducer (i.e., inducer specificity) or on the capacity of hepatocytes located in different acinar zones to respond to inducers (i.e. zonal specificity), the pattern of acinar induction was evaluated following treatment with inducers that have diverse physiochemical properties and inductive capacities. The zonal distribution of P-450b and P-450e mRNAs in liver was determined by in situ hybridization after the administration of either phenobarbital, polychlorinated biphenyls, chlordane, or chlorpromazine. Liver sections were hybridized with 3H-labeled RNA transcripts of a P-450e cDNA that recognizes sequences of both P-450b and P-450e mRNAs and the pattern of zonal mRNA induction was measured by quantitative image analysis. Each inducer increased P-450b,e mRNA levels predominantly in hepatocytes of zones 2 and 3 of the hepatic acinus. The P-450b and P-450e apoproteins were induced in the same zonal hepatocytes as the P-450b,e mRNAs as shown by immunofluorescence studies using monoclonal antibodies. Therefore, differential transcriptional induction of the P-450IIB genes in the liver acinus does not seem to be dependent on a specific chemical inducer, but rather is a characteristic capacity of hepatocytes located in different acinar zones. To determine whether the induction of P-450b and P-450e was dependent on the liver tissue organization, hepatocytes were isolated by collagenase perfusion of the liver and transplanted into the spleens of syngeneic rats. Induction of P-450b and P-450e mRNAs and apoproteins, assessed 1 month after transplantation, was evident with each of the chemical inducers. These data suggest that, once hepatocytes have attained the capacity to respond to inducers, the organization of hepatocytes into acini and the sinusoidal microenvironment of the liver are not required for hepatocytes to maintain the ability to respond to inducers with an increase in transcription of P-450IIB genes. Moreover, the splenic hepatocytes demonstrated a heterogeneous pattern of P-450b,e apoprotein induction; this raises the possibility that the acinar organization is also not required for the heterogenous expression of P-450IIB genes.

The components of the plastid ribosome are not accumulated synchronously during the early development of spinach plants

The expression of components of the 70S plastid ribosome has been determined during the first 13 days of spinach plant development. Total cellular RNA and proteins were used to determine the relative steady-state levels of mRNA for ribosomal proteins (r-proteins) by dot blot hybridization and the relative amounts of proteins by immunodetection with specific antibodies. The 16S rRNA as well as mRNAs for 9 out of 11 proteins studied, including those for the 32 kDa polypeptide of photosystem II and the large subunit (LSU) of ribulose-1,5-bisphosphate carboxylase (Rubisco) show a marked increase at the beginning of the germination (day 5). At this time the plastid DNA content increases from 4% to 6% of total DNA content and so the plastome copy number can only in part account for the important increase in mRNA steady-state levels. Interestingly the transcripts of the rpl23 and rps19 genes show a different accumulation pattern, indicating either a differential gene transcription and/or an increased stability of the transcripts. In the western blot analysis a group of r-proteins can be detected in dry seeds or after 24 hours of imbibition while a second group of proteins accumulates after 3 to 5 days of development. The differential accumulation pattern of r-proteins and mRNA for r-proteins indicates that post-transcriptional control plays an important role in plastid r-protein synthesis.

Effects of liquid diet on amylase activity and mRNA levels in rat parotid gland

Rats maintained on this diet demonstrated a dramatic reduction in amylase enzyme activity. This reduced level was evident through quantitation based on activity per mg gland protein, as well as on activity per gland wet weight. This was confirmed by the densitometric scanning of Western blots of sodium dodecyl sulphate-polyacrylamide gels of total parotid gland protein. Immune precipitation of enzyme activity from cell lysates showed that liquid-diet animals had lower levels of amylase than chow-fed controls. Isolation of poly (A +)-containing RNA followed by in vitro translation indicated that the steady-state level of amylase-specific mRNA had increased relative to the total mRNA pool. This outcome was also observed by dot-blot analysis of the cellular RNA using an amylase cDNA probe. Thus the regulation of amylase synthesis in rats maintained on liquid diets may take place at the level of protein translation, as well as of differential mRNA stability or gene transcription.

Transcription Unit of the Rabbit β1 Globin Gene

We have hybridized pulse-labeled nuclear transcripts to cloned DNA fragments from the rabbit beta-like globin genes to determine the developmental timing, extent, and asymmetry of their transcription. The fetal-adult gene beta 1 was transcribed in fetal liver but not embryonic nuclei, whereas genes beta 3 and beta 4, which encode embryonic globin polypeptides, were transcribed only in embryonic nuclei. This shows that the switch from embryonic to fetal-adult globin production in rabbits is accomplished primarily by differential transcription of the beta-like globin genes. Gene beta 1 was subdivided into M13 subclones and tested for hybridization to nascent RNA. The nucleotide sequence of the 3' flanking region of gene beta 1 was also determined for 2,447 base pairs past the polyadenylation [poly(A)] site. No transcripts were found 5' to the cap site, but asymmetric transcription of gene beta 1 proceeded at a high level through the gene and past the poly(A) addition site for 603 nucleotides. The level of transcription declined after this, gradually dropping through the next 568 nucleotides. No polymerases were found on a fragment that begins 1,707 nucleotides past the poly(A) site; this fragment was part of a segment of repetitive DNA. These data show that the transcription unit of gene beta 1 begins at or near the cap nucleotide and extends at least 1,171 but no more than 1,706 nucleotides past the poly(A) addition site. The DNA segment that precedes the region of declining transcription contained an inverted repeat and encoded a short RNA transcribed by RNA polymerase II from the strand opposite the beta 1 transcript. These two features may function to attenuate the transcription of gene beta 1. An inverted repeat and a potential polymerase II transcription unit were also found in the homologous segment 3' to the human beta-globin gene. A short DNA segment close to the 3' end of the beta 1 transcription unit was transcribed more actively than the surrounding DNA, and it contained sequences that match the consensus internal control region for RNA polymerase III. This DNA segment may contain a separate polymerase III transcription unit. A member of the D repeat family located 3' to gene beta 1 was not transcribed in its entirety coordinately with beta 1.

Transcription unit of the rabbit beta 1 globin gene.

We have hybridized pulse-labeled nuclear transcripts to cloned DNA fragments from the rabbit beta-like globin genes to determine the developmental timing, extent, and asymmetry of their transcription. The fetal-adult gene beta 1 was transcribed in fetal liver but not embryonic nuclei, whereas genes beta 3 and beta 4, which encode embryonic globin polypeptides, were transcribed only in embryonic nuclei. This shows that the switch from embryonic to fetal-adult globin production in rabbits is accomplished primarily by differential transcription of the beta-like globin genes. Gene beta 1 was subdivided into M13 subclones and tested for hybridization to nascent RNA. The nucleotide sequence of the 3' flanking region of gene beta 1 was also determined for 2,447 base pairs past the polyadenylation [poly(A)] site. No transcripts were found 5' to the cap site, but asymmetric transcription of gene beta 1 proceeded at a high level through the gene and past the poly(A) addition site for 603 nucleotides. The level of transcription declined after this, gradually dropping through the next 568 nucleotides. No polymerases were found on a fragment that begins 1,707 nucleotides past the poly(A) site; this fragment was part of a segment of repetitive DNA. These data show that the transcription unit of gene beta 1 begins at or near the cap nucleotide and extends at least 1,171 but no more than 1,706 nucleotides past the poly(A) addition site. The DNA segment that precedes the region of declining transcription contained an inverted repeat and encoded a short RNA transcribed by RNA polymerase II from the strand opposite the beta 1 transcript. These two features may function to attenuate the transcription of gene beta 1. An inverted repeat and a potential polymerase II transcription unit were also found in the homologous segment 3' to the human beta-globin gene. A short DNA segment close to the 3' end of the beta 1 transcription unit was transcribed more actively than the surrounding DNA, and it contained sequences that match the consensus internal control region for RNA polymerase III. This DNA segment may contain a separate polymerase III transcription unit. A member of the D repeat family located 3' to gene beta 1 was not transcribed in its entirety coordinately with beta 1.

Electron Microscopic Analysis of Asymmetry within the Cell Nucleus of DNA Helix Openings During Human Cell Activation and Cell Differentiation

Most of the DNA molecules within an animal cell are repressed for RNA synthesis at any one time, and those DNA molecules that are active are characteristic of the particular tissue or organ within which the cell has differentiated (1). This phenomena of differential gene transcription is thought to be the epigenetic basis for such diverse cell activities as cell differentiation organ regeneration, neoplastic transformation, immune activation, and the response to steroid hormones (2). Carcinogenic chemicals, oncogenic viruses, embryogenic RNA, immune RNA, and steroid hormones all prefer to bind to single-stranded regions within DNA molecules of the host cell (3). DNA molecules which are active in RNA synthesis display short loops of such single-stranded DNA (4), which are a necessary prerequisite for the gene de-repression characteristic of animal neoplasms (5).

Two-dimensional gel analysis of nuclear proteins during muscle differentiation in vitro: I. Changes in nuclear protein content

Improved methods are described for the isolation of nuclei from skeletal muscle-cell cultures by lysis with Triton X-100 and centrifugation through 65% sucrose-5 mM MgCl 2. Evidence is presented that levels of contamination by cytoplasmic and fibrillar proteins are acceptably low. Nuclear proteins were separated into saline-soluble and non-histone protein (NHP) fractions and analysed on two-dimensional gels stained with Coomassie Blue. 2D-gels of NHP and cytoplasmic proteins were compared and few proteins common to both fractions were found. Of three major cytoplasmic proteins, actin, tubulin and tropomyosin, only actin could be positively identified as a minor protein in NHP and tropomyosin was undetectable. An overall increase in nuclear NHP content (relative to DNA) occurred during the early period of cell differentiation in vitro (24–66 h of culture) and a corresponding increase in nuclear protein to DNA ratio was observed. There were differential changes between individual NHP, some major proteins showing little change, while others showed large increases. These changes may be related to increases in nuclear protein uptake which are reported to occur during differentiation and hormone-induced gene transcription in other cell types.

Actin-like protein of the cytoplasm in the chromatin of Dictyostelium discoideum

The cellular slime mould, Dictyostelium discoideum, is an attractive eukaryotic microorganism for studies on cellular development and differential gene expression [ 11. The genome has a low complexity, only 7 times that of Escherichia coli [2]. A large fraction of the chromatin is active as template [3] and the developmental cycle is determined, at least in part, by differential gene transcription [4]. Here we describe the purification of chromatin from different stages of development. Two methods were used for the isolation of nuclei, one applying 1% Triton X-100 and the other without use of a detergent. Washing a crude nuclear fraction with 1% Triton X-100 buffer resulted in an enrichment of two polypeptides among the chromatin proteins with mol. wt 44 000 and 180 000, respectively (designated 44 k and 180 k). The 44 k polypeptide was selectively absorbed from the cytoplasm. Partial peptide mapping (not shown) revealed similarity with rabbit muscle actin. The results suggest that recent publications which report actin and myosin as chromatin constituents, dealt with cytoplasmic contaminations since they all employed a nonionic detergent for lysing cells and purifying nuclei.

Attenuation as a general mechanism for the regulation of differential gene transcription in eukaryotes

FEBS LettersVolume 100, Issue 2 p. 225-229 Full-length articleFree Access Attenuation as a general mechanism for the regulation of differential gene transcription in eukaryotes J.A. Remington, J.A. Remington Département de biologie, Université Laval, Québec GPK 7P4, PQ CanadaSearch for more papers by this author J.A. Remington, J.A. Remington Département de biologie, Université Laval, Québec GPK 7P4, PQ CanadaSearch for more papers by this author First published: April 15, 1979 https://doi.org/10.1016/0014-5793(79)80339-7Citations: 20AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References 1 F. Lee, Y. Yanofsky, Proc. Natl. Acad. Sci. USA, 74, (1977), 4365– 4369. 2 S. Goldberg, H. Schwartz, J.E. Darnell, Proc. Natl. Acad. Sci. USA, 74, (1977), 4520– 4523. 3 R.W. Shearer, E. Smuckler, Cancer Res., 32, (1972), 339– 343. 4 P. O'Farrell, B. Cordell, P. Valenzuela, J. Rutter, H. Goodman, Nature, 274, (1978), 438– 445. 5 S.M. Tilghman, P. Curtis, D. Tiemeier, P. Leder, C. Weissmann, Proc. Natl. Acad. Sci. USA, 75, (1978), 1309– 1313. 6 N.J. Proudfoot, G. Brownlee, Nature, 263, (1976), 211– 215. 7 F.E. Baralle, Nature, 267, (1977), 279– 282. 8 F. Crick, Nature, 234, (1971), 25– 28. 9 R.J. Britten, E.H. Davidson, Science, 165, (1969), 349– 356. 10 G.P. Georgiev, J. Theor. Biol., 25, (1969), 473– 484. 11 W. Salser, Cold Spring Harbor Symp. Quant. Biol., 42, (1978), 985– 1002. 12 J. Paul, R.S. Gilmour, J. Mol. Biol., 34, (1968), 305– 314. 13 G.S. Stein, T.C. Spelsberg, L.J. Kleinsmith, Science, 183, (1974), 817– 824. 14 T.C. Spelsberg, W.M. Mitchell, F. Chytil, E. Wilson, B. O'Malley, Biochim. Biophys. Acta, 312, (1973), 765– 777. 15 M. Zazloff, G. Felsenfeld, Biochemistry, 16, (1977), 5135– 5142. 16 P. Chambon, Cold Spring Harbor Symp. Quant. Biol., 42, (1978), 1209– 1234. 17 H.C. Towle, M.J. Tsai, S.Y. Tsai, B.W. O'Malley, J. Biol. Chem., 252, (1977), 2396– 2401. 18 C. Dierks-Ventling, Nucl. Acids Res., 5, (1978), 3929– 3943. 19 R.D. Palmiter, E. Mulvihill, G. McKnight, A. Senear, Cold Spring Harbor Symp. Quant. Biol., 42, (1978), 639– 647. 20 S. Orkin, P. Swerdlow, Proc. Natl. Acad. Sci. USA, 74, (1977), 2475– 2479. 21 L. Kleene, T. Humphreys, Cell, 12, (1977), 143– 155. 22 M. Melli, G. Spinelli, E. Aranold, Cell, 12, (1977), 167– 174. 23 R.L. Jansing, J. Stein, G.S. Stein, Proc. Natl. Acad. Sci. USA, 74, (1977), 173– 177. 24 G. Ryffel, B. McCarthy, Biochemistry, 14, (1975), 1379– 1384. 25 N. Hastie, J.O. Bishop, Cell, 9, (1976), 761– 774. 26 B. Young, G. Birnie, J. Paul, Biochemistry, 15, (1976), 2823– 2829. 27 D. Chikaraishi, S. Deeb, N. Sueoka, Cell, 13, (1978), 111– 120. 28 B. Hough, M. Smith, R. Britten, E.H. Davidson, Cell, 5, (1975), 291– 299. 29 A. Mauron, G. Spohr, Nucl. Acids Res., 5, (1978), 3013– 3032. 30 T. Kasai, Nature, 249, (1974), 523– 527. 31 G.V. Stauffer, G. Zurawski, C. Yanofsky, Proc. Natl. Acad. Sci. USA, 75, (1978), 4833– 4837. 32 W.M. Barnes, Proc. Natl. Acad. Sci. USA, 75, (1978), 4281– 4285. 33 G. Zurawski, K. Brown, D. Killingly, C. Yanofsky, Proc. Natl. Acad. Sci. USA, 75, (1978), 4271– 4275. 34 S. Tsai, M. Tsai, R. Schwartz, M. Kalimi, J. Clark, B. O'Malley, Proc. Natl. Acad. Sci. USA, 72, (1975), 4228– 4233. 35 L. Goldstein, G. Wise, C. Ko, J. Cell Biol., 73, (1977), 322– 331. 36 J.H. Frenster, Cancer Res., 36, (1976), 3394– 3398. 37 M.O. Krause, M. Ringuette, Biochem. Biophys. Res. Commun., 76, (1977), 796– 803. 38 A. Deshpande, S. Jakowlew, H. Arnold, P. Crawford, M. Siddiqui, J. Biol. Chem., 252, (1977), 6521– 6527. 39 T. Kanehisa, Y. Kitazume, I. Kazuyoshi, Y. Tanaka, Biochim. Biophys. Acta, 475, (1977), 501– 513. 40 Y. Kano, H. Komatsu, K. Nakawoin, Y. Fujiwara, Exp. Cell Res., 115, (1978), 444– 448. 41 W. Jelinek, L. Leinwand, Cell, 15, (1978), 205– 214. 42 J. Shine, L. Dalgarno, Proc. Natl. Acad. Sci. USA, 71, (1974), 1342– 1346. 43 M. Kozak, Cell, 15, (1978), 1109– 1123. 44 D. Holmes, J. Mayfield, J. Bonner, Biochemistry, 13, (1974), 849– 855. 45 R.A. Weinberg, Ann. Rev. Biochem., 42, (1973), 329– 354. 46 I. Tamm, Proc. Natl. Acad. Sci. USA, 74, (1977), 5011– 5015. 47 B. Wold, W. Klein, B. Hough-Evans, R. Britten, E.H. Davidson, Cell, 14, (1978), 941– 950. Citing Literature Volume100, Issue2April 15, 1979Pages 225-229 ReferencesRelatedInformation

Developmental changes in RNA and protein synthesis during germination of Dictyostelium discoideum spores

Spore germination in Dictyostelium discoideum is a synchronous developmental process involving three distinct stages: activation, swelling, and emergence of amoebae. The regulation of protein and RNA synthesis during normal germination in the wild-type D. discoideum has been compared with the events that occur during abortive germination of mutant HE-1 and cycloheximide-treated wild-type spores, both of which are blocked at the emergence stage. Some aspects of the regulation of the synthesis of different types of RNA were investigated. RNA was isolated from germinating spores labeled at hourly intervals after activation. The RNA was fractionated by oligo(dT)-cellulose chromatography and sucrose density gradient centrifugation. Analysis of the RNA shows that the synthesis of mRNA, tRNA, and rRNA is developmentally regulated during germination. During the initial stages, the majority of the RNA made is mRNA and tRNA, while during later stages of germination, more rRNA is synthesized. In order to detect the presence of functional mRNA at different stages, RNA was isolated from dormant and germinating spores. Translatable mRNA was assayed by the ability of the RNA to stimulate incorporation of radioactive amino acids into protein in a wheat germ cell-free extract. The results show that dormant spores contain translatable polyadenylated mRNA, and the fraction of total RNA with mRNA activity increases during germination. From an analysis of the proteins synthesized during germination, it is evident that the synthesis of proteins is also developmentally regulated. Four classes of proteins could be distinguished on gels, depending on the time of onset and duration of their synthesis. A comparison of proteins made in vivo with those synthesized in vitro indicates that there are qualitative changes in the population of translatable mRNAs during germination, presumably due to differential gene transcription. Some of these changes observed in vitro correlate well with the differences in proteins synthesized in intact germinating spores. RNA and protein synthesis were compared in mutant HE-1 and in wild-type germination. In the mutant, unlike the wild type, there is no change in the proportion of mRNA made during germination, and rRNA represents a smaller portion of the total RNA made at any interval than in the wild type. In addition, it is noteworthy that the pattern of protein synthesis during abortive germination in the mutant is very different from that observed in the wild type. The control over the synthesis of different types of RNA and proteins during germination appears abnormal in the mutant, suggesting that developmental regulation is defective in the mutant.