Induction of cell-specific ribosomal proteins in aggregation-competent nonmorphogenetic Dictyostelium discoideum

1990 ◽  
Vol 68 (11) ◽  
pp. 1281-1287 ◽  
Author(s):  
S. Ramagopal
Keyword(s):  
Ribosomal Proteins ◽  
Cell Types ◽  
Growth Cycle ◽  
Logarithmic Phase ◽  
Cellular Slime Mold ◽  
Developmentally Regulated ◽  
Vegetative Cells ◽  
Competent Cells ◽  
Cellular Slime ◽  
Different Cell Types

Vegetatively growing amoebae, if shaken in a starvation (nonnutrient) buffer, acquire aggregation competence, but do not embark on a morphogenetic program. The quantitative variation of ribosomal proteins in vegetative and aggregation-competent cells was compared by labeling the different cell types with [35S]methionine. Vegetative cells were examined at various phases of the growth cycle. No changes could be detected in the content of ribosomes or the apparent stoichiometry of ribosomal proteins in growing cells. In stationary phase cells, the net ribosome content declined to 15% of that observed in logarithmic phase, but the relative amounts of individual ribosomal proteins were not altered. Although aggregation-competent cells contained 30% less ribosomes compared with logarithmic phase cells, the total fraction of newly made ribosomal proteins was the same in both. In contrast to vegetative cells, distinct changes were induced in the ribosomal proteins of aggregation-competent cells. The composition of ribosomes in aggregation-competent phase resembled in every respect that observed in spore cells. As reported earlier, changes were found in all 12 of the developmentally regulated ribosomal proteins. For the majority of newly made ribosomal proteins during aggregation competence, the stoichiometry was similar to that in logarithmically growing cells. However, the relative synthesis of some was particularly higher (13- to 46-fold for A and L; 3- to 8-fold for D, E, S24, L3, S6, and L4) compared with logarithmic phase cells. About 18 proteins, which included the cell-specific ribosomal proteins L18, S10, S14, S16, and L11, were synthesized in lesser amounts than in logarithmic phase cells. It is concluded that the attainment of aggregation competence is sufficient for the induction of spore cell specific ribosomal proteins in Dictyostelium discoideum.Key words: cellular slime mold, ribosomal proteins, development.

Differences in accumulation and phosphorylation of proteins in vegetatively growing and aggregation-competent cells of Dictyostelium discoideum

1991 ◽  
Vol 69 (10-11) ◽  
pp. 751-753
Author(s):  
S. Ramagopal
Keyword(s):  
Ribosomal Proteins ◽  
Staining Method ◽  
Cellular Slime Mold ◽  
Developmentally Regulated ◽  
Two Dimensional Gel Electrophoresis ◽  
Competent Cells ◽  
In Vivo Labeling ◽  
Cellular Slime ◽  
Silver Staining Method

A comparison of proteins from whole cell lysates of vegetative amoebae and aggregation-competent cells by high-resolution two-dimensional gel electrophoresis coupled with a sensitive silver staining method revealed distinct differences. In aggregation-competent cells, 16 proteins present in the vegetative amoebae disappeared, and 25 new proteins appeared. A few other proteins showed quantitative variation during the transition of vegetative amoebae to aggregation competence. Identification of phosphoproteins by in vivo labeling with [32P]orthophosphate showed that none of the developmentally regulated cellular proteins were modified. Phosphorylation was observed in four proteins. One protein was phosphorylated exclusively in aggregation-competent cells. The phosphorylation level of two other proteins was higher in aggregation-competent cells compared with vegetative amoebae. The data suggest that phosphorylation of cellular and certain ribosomal proteins may be regulated coordinately in Dictyostelium discoideum.Key words: cellular slime mold, cell differentiation, protein phosphorylation.

Subcellular distribution of ribosomal proteins in Dictyostelium discoideum

1990 ◽  
Vol 68 (5) ◽  
pp. 839-845
Author(s):  
S. Ramagopal
Keyword(s):  
Ribosomal Proteins ◽  
Large Subunit ◽  
Small Subunit ◽  
Cellular Slime Mold ◽  
Developmentally Regulated ◽  
Two Dimensional Gel Electrophoresis ◽  
Coomassie Blue ◽  
Cellular Slime ◽  
State Growth

The distribution of ribosomal proteins in monosomes, polysomes, the postribosomal cytosol, and the nucleus was determined during steady-state growth in vegetative amoebae. A partitioning of previously reported cell-specific ribosomal proteins between monosomes and polysomes was observed. L18, one of the two unique proteins in amoeba ribosomes, was distributed equally among monosomes and polysomes. However S5, the other unique protein, was abundant in monosomes but barely visible in polysomes. Of the developmentally regulated proteins, D and S6 were detectable only in polysomes and S14 was more abundant in monosomes. The cystosol revealed no ribosomal proteins. On staining of the nuclear proteins with Coomassie blue, about 18, 7 from 40S subunit and 11 from 60S subunit, were identified as ribosomal proteins. By in vivo labeling of the proteins with [35S]methionine, 24 of the 34 small subunit proteins and 33 of the 42 large subunit proteins were localized in the nucleus. For the majority of the ribosomal proteins, the apparent relative stoichiometry was similar in nuclear preribosomal particles and in cytoplasmic ribosomes. However, in preribosomal particles the relative amount of four proteins (S11, S30, L7, and L10) was two- to four-fold higher and of eight proteins (S14, S15, S20, S34, L12, L27, L34, and L42) was two- to four-fold lower than that of cytoplasmic ribosomes.Key words: cellular slime mold, cell-specific ribosomal proteins, nucleus, cytoplasm, two-dimensional gel electrophoresis.

Acidic ribosomal proteins of Dictyostelium discoideum that show electrophoretic similarity to Escherichia coli proteins L7 and L12

1989 ◽  
Vol 67 (10) ◽  
pp. 712-718 ◽  
Author(s):  
S. Ramagopal
Keyword(s):  
Escherichia Coli ◽  
Dictyostelium Discoideum ◽  
Gel Electrophoresis ◽  
Ribosomal Proteins ◽  
Sodium Dodecyl ◽  
Slime Mold ◽  
Cellular Slime Mold ◽  
Two Dimensional ◽  
Cellular Slime ◽  
Acidic Proteins

This study documents the presence of three acidic proteins, A1 (pI 4.95), A2 (pI 4.85), and A3 (pI 4.70), in Dictyostelium discoideum ribosomes. All three proteins showed an apparent molecular mass of 13 000 by two-dimensional, sodium dodecyl sulfate gel electrophoresis. They were selectively released by treatment of ribosomes with 50% ethanol – 1 M NH4Cl. The amino acid compositions of A1, A2, and A3 were identical and indicated a predominant amount of alanine. All the above properties are shared by Escherichia coli proteins L7 and L12 and acidic ribosomal proteins in many eukaryotes. Unlike other eukaryotic systems, the acidic proteins of D. discoideum were found associated with the 40S rather than the 60S ribosomal subunit. Acidic proteins analogous in size and electrophoretic mobility to those of D. discoideum were also detected in several other cellular slime mold strains. Not one of the cellular slime mold acidic proteins reacted with antibodies to E. coli proteins L7 and L12 in immunodiffusion tests. In D. discoideum, the distribution of acidic proteins was altered during development. Amoebae contained all three proteins. In spores, A, was absent and the relative amounts of A2 and A3 were lower than in amoebae. In addition, nine other acidic ribosomal proteins exhibited differences between vegetative amoebae and spores.Key words: acidic ribosomal proteins, development, cellular slime mold, L7 and L12 proteins, two-dimensional gel electrophoresis.

scholarly journals The Heterocyst-Specific NsiR1 Small RNA Is an Early Marker of Cell Differentiation in Cyanobacterial Filaments

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Alicia M. Muro-Pastor
Keyword(s):  
Small Rna ◽  
Single Cells ◽  
Nitrogen Deficiency ◽  
Cell Types ◽  
Nitrogen Fixing ◽  
Vegetative Cells ◽  
Early Marker ◽  
Multicellular Organisms ◽  
Pcc 7120 ◽  
Different Cell Types

ABSTRACT Differentiation of single cells along filaments of cyanobacteria constitutes one of the simplest developmental patterns in nature. In response to nitrogen deficiency, certain cells located in a semiregular pattern along filaments differentiate into specialized nitrogen-fixing cells called heterocysts. The process involves the sequential activation of many genes whose expression takes place, either exclusively or at least more strongly, in those cells undergoing differentiation. In the model cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120, increased transcription of hetR, considered the earliest detectable heterocyst-specific transcript, has been reported to occur in pairs or even in clusters of cells, thus making it difficult to identify prospective heterocysts during the early stages of differentiation, before any morphological change is detectable. The promoter of nsiR1 (nitrogen stress inducible RNA1), a heterocyst-specific small RNA, constitutes a minimal sequence promoting heterocyst-specific transcription. Using confocal fluorescence microscopy, I have analyzed expression of a gfp reporter transcriptionally fused to P nsiR1 . The combined analysis of green fluorescence (reporting transcriptional activity from P nsiR1 ) and red fluorescence (an indication of progress in the differentiation of individual cells) shows that expression of P nsiR1 takes place in single cells located in a semiregular pattern before any other morphological or fluorescence signature of differentiation can be observed, thus providing an early marker for cells undergoing differentiation. IMPORTANCE Cyanobacterial filaments containing heterocysts constitute an example of bacterial division of labor. When using atmospheric nitrogen, these filaments behave as multicellular organisms in which two different cell types (vegetative cells and nitrogen-fixing heterocysts) coexist and cooperate to achieve growth of the filament as a whole. The molecular basis governing the differentiation of individual vegetative cells, and thus the establishment of a one-dimensional pattern from cells that are apparently the same, remains one of the most intriguing aspects of this differentiation process. Recent evidence suggests that, at any given time, some cells in the filaments are more likely than others to become heterocysts when nitrogen limitation is encountered. The robust heterocyst-specific nsiR1 promoter, which is induced very early during differentiation, provides a valuable tool to analyze issues such as early candidacy or the possible role of transcriptional noise in determining the fate of specific cells in cyanobacterial filaments.

Unequal accumulation of 26S and 17S RNAs in ribosomes during spore germination in Dictyostelium discoideum

1989 ◽  
Vol 35 (9) ◽  
pp. 850-853
Author(s):  
S. Ramagopal
Keyword(s):  
Cell Differentiation ◽  
Dictyostelium Discoideum ◽  
Spore Germination ◽  
Ribosomal Proteins ◽  
Rrna Synthesis ◽  
Cellular Slime Mold ◽  
Stoichiometric Ratio ◽  
Relative Level ◽  
Ribosome Synthesis ◽  
Cellular Slime

Ribosome synthesis was studied in spores at the swelling stage and compared with freshly emerged and logarithmically growing vegetative amoebae. During the swelling stage of spore germination, ribosome synthesis was abnormal. Newly made ribosomes accumulated unequal amounts of 26S and 17S rRNAs. The stoichiometric ratio 26S:17S was 0.5 in swelling spores, compared with 0.9 in amoebae. The relative level of pre-rRNA persisting in the nucleus was apparently 2- to 3-fold higher in swelling spores than in amoebae. All of the known ribosomal proteins, except for a few, were made during the swelling stage and were associated with the newly made ribosomes in expected amounts. Analysis of the 2′-O-methyl ribose content in the newly made rRNAs suggests that methylation was defective in swelling spores. Compared with growing amoebae, the methyl content was 30 and 64% less in 26S and 17S RNAs from the swelling stage, respectively. It is suggested that undermethylation could be partly responsible for the differential accumulation of newly made 26S and 17S RNAs during the early stages of spore germination in Dictyostelium discoideum.Key words: cellular slime mold, rRNA synthesis, ribosomal proteins, methylation, cell differentiation.

Purification and characterization of histone H1 from meiotic cells of a monocotyledonous plant, Lilium longiflorum

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 736-741 ◽  
Author(s):  
C. Daniel Riggs
Keyword(s):  
Lilium Longiflorum ◽  
Cell Types ◽  
Histone H1 ◽  
Cellular Protein ◽  
Vegetative Cells ◽  
Unbound Fraction ◽  
Total Cellular Protein ◽  
The Difference ◽  
Different Cell Types ◽  
Sulfuric Acid Solutions

To identify molecules involved in regulating meiotic chromatin structure, nuclear proteins from meiocytes of Lilium longiflorum were chromatographed on hydroxylapatite and the bound and unbound proteins were examined. An abundant nuclear protein was purified from the unbound fraction and by the following criteria was identified as a histone H1 molecule. The protein is soluble in acidic (perchloric and sulfuric acid) solutions, and its amino acid composition and the sequence of its amino terminus are similar to that of known histone H1s. An antiserum was produced against the protein to facilitate subsequent studies. Immunoblotting experiments demonstrated that histone H1 immunostaining declines in the developmental interval spanning the diplotene to tetrads stages. Concommitant with this decline is the appearance of several lower molecular mass, cross-reacting proteins. Neither the identity nor roles of these proteins is known. Immunoblotting experiments also demonstrate that, while the level of the protein is relatively constant in nuclei prepared from meiotic and vegetative cells, histone H1 is apparently enriched in total cellular extracts of meiotic cells compared with vegetative cells. This difference was found to be at least 16-fold. I conclude that in meiotic cells, histone H1 accounts for more of the total cellular protein than it does in vegetative cells. The difference in its relative abundance as a percent of the total cellular protein is probably in part due to differences in the ratio of nuclear to cytoplasmic volume in the different cell types, or the purging of sporophytic proteins from the cytoplasm of the meiocytes, or both.Key words: meiosis, histone H1, immunoblotting, meiotic purging.

scholarly journals The Modular Adaptive Ribosome

2016 ◽  
Author(s):  
Anupama Yadav ◽  
Aparna Radhakrishnan ◽  
Anshuman Panda ◽  
Amartya Singh ◽  
Himanshu Sinha ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Large Data ◽  
Cell Types ◽  
Ecological Niches ◽  
Environmental Cues ◽  
Dependent Manner ◽  
Yeast Strains ◽  
Specific Manner ◽  
Signatures Of Selection ◽  
Different Cell Types

ABSTRACTThe ribosome is an ancient machine, performing the same function across organisms. Although functionally unitary, recent experiments suggest specialized roles for some ribosomal proteins. Our central thesis is that ribosomal proteins function in a modular fashion to decode genetic information in a context dependent manner. We show through large data analyses that although many ribosomal proteins are essential with consistent effect on growth in different conditions in yeast and similar expression across cell and tissue types in mice and humans, some ribosomal proteins are used in an environment specific manner. The latter set of variable ribosomal proteins further function in a coordinated manner forming modules, which are adapted to different environmental cues in different organisms. We show that these environment specific modules of ribosomal proteins in yeast have differential genetic interactions with other pathways and their 5’UTRs show differential signatures of selection in yeast strains, presumably to facilitate adaptation. Similarly, we show that in higher metazoans such as mice and humans, different modules of ribosomal proteins are expressed in different cell types and tissues. A clear example is nervous tissue that uses a ribosomal protein module distinct from the rest of the tissues in both mice and humans. Our results suggest a novel stratification of ribosomal proteins that could have played a role in adaptation, presumably to optimize translation for adaptation to diverse ecological niches and tissue microenvironments.

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