Ectopic Expression of the NtSET1 Histone Methyltransferase Inhibits Cell Expansion, and Affects Cell Division and Differentiation in Tobacco Plants

ABSTRACT Regulated cyclin-dependent kinase (CDK) levels and activities are critical for the proper progression of the cell division cycle. p12DOC-1 is a growth suppressor isolated from normal keratinocytes. We report that p12DOC-1 associates with CDK2. More specifically, p12DOC-1 associates with the monomeric nonphosphorylated form of CDK2 (p33CDK2). Ectopic expression of p12DOC-1 resulted in decreased cellular CDK2 and reduced CDK2-associated kinase activities and was accompanied by a shift in the cell cycle positions of p12DOC-1transfectants (↑ G1 and ↓ S). The p12DOC-1-mediated decrease of CDK2 was prevented if the p12DOC-1 transfectants were grown in the presence of the proteosome inhibitor clasto-lactacystin β-lactone, suggesting that p12DOC-1 may target CDK2 for proteolysis. A CDK2 binding mutant was created and was found to revert p12DOC-1-mediated, CDK2-associated cell cycle phenotypes. These data support p12DOC-1 as a specific CDK2-associated protein that negatively regulates CDK2 activities by sequestering the monomeric pool of CDK2 and/or targets CDK2 for proteolysis, reducing the active pool of CDK2.

Download Full-text

Control of GL2 expression in Arabidopsis leaves and trichomes

Development ◽

10.1242/dev.125.7.1161 ◽

1998 ◽

Vol 125 (7) ◽

pp. 1161-1171 ◽

Cited By ~ 6

Author(s):

D.B. Szymanski ◽

R.A. Jilk ◽

S.M. Pollock ◽

M.D. Marks

Keyword(s):

Cell Expansion ◽

Expression Patterns ◽

Ectopic Expression ◽

Spatial And Temporal Variation ◽

R Gene ◽

Gus Reporter ◽

Transparent Testa ◽

Initial Selection ◽

Epistatic Analysis ◽

Selection Of

More than twenty genes are required for the correct initiation, spacing, and morphogenesis of trichomes in Arabidopsis. The initial selection of trichome precursors requires the activity of both the GLABROUS1 (GL1) and TRANSPARENT TESTA GLABROUS (TTG) genes. The GLABRA2 (GL2) gene is required for subsequent phases of trichome morphogenesis such as cell expansion, branching, and maturation of the trichome cell wall. Previous studies have shown that GL2 is a member of the homeodomain class of transcription factors. Here we report a detailed analysis of GL2 expression in the shoot using anti-GL2 antibodies and the GUS reporter gene fused to the GL2 promoter. The GL2 expression profile in the shoot is complex, and involves spatial and temporal variation in developing leaves and trichomes. Two separate promoter domains that are expressed in trichomes were identified. GL2, like GL1, is expressed in developing trichomes and in cells surrounding trichomes during early stages of trichome development. Unlike GL1, GL2 expression persists in mature trichomes. It was found that while GL1 and TTG were not required for the initiation of GL2 expression in the non-trichome cells, the presence of a functional GL1 or TTG gene was able to increase GL2 expression in these cells compared to ttg gl1 plants. The hypothesis that GL1 regulates aspects of GL2 expression is consistent with epistatic analysis of gl1 and gl2 and the expression patterns of GL1 and GL2. In support of this hypothesis, it was found that ectopic expression of GL1 in the presence of ectopic expression of the maize R gene, which can bypass the requirement for TTG, can ectopically activate GL2 transcription.

Download Full-text

Plants expressing murine pro-apoptotic protein Bid do not have enhanced PCD

BMC Research Notes ◽

10.1186/s13104-020-05285-x ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Anna Manara ◽

Zahra Imanifard ◽

Linda Fracasso ◽

Diana Bellin ◽

Massimo Crimi

Keyword(s):

Cell Death ◽

Stress Responses ◽

Growth And Development ◽

Active Form ◽

Ectopic Expression ◽

Signaling Cascade ◽

Tobacco Plants ◽

Truncated Protein ◽

Apoptotic Protein ◽

Family Protein

Abstract Objectives The purpose of this study was to explore whether plant programmed cell death (PCD) cascade can sense the presence of the animal-only BH3 protein Bid, a BCL-2 family protein known to play a regulatory role in the signaling cascade of animal apoptosis. Results We have expressed the mouse pro-apoptotic protein Bid in Arabidopsis thaliana and in Nicotiana tabacum. We did not obtain any transformed plant constitutively expressing the truncated protein (tBid—i.e. the caspase-activated form) whereas ectopic expression of the full-length protein (flBid) does not interfere with growth and development of the transformed plants. To verify whether the presence of this animal pro-apoptotic protein modified stress responses and PCD execution, both N. tabacum and A. thaliana plants constitutively expressing flBid have been studied under different stress conditions triggering cell death activation. The results show that the presence of flBid in transgenic plants did not significantly change the responses to abiotic stress (H2O2 or NO) and biotic stress treatments. Moreover, the finding that no Bid active form was present in treated tobacco plants suggests an absence of a proper activation of Bid.

Download Full-text

Separation of Mechanisms Initiating Cell Division and Cell Expansion in Lettuce Seed Germination

PLANT PHYSIOLOGY ◽

10.1104/pp.35.2.168 ◽

1960 ◽

Vol 35 (2) ◽

pp. 168-173 ◽

Cited By ~ 65

Author(s):

Alan H. Haber ◽

Helen J. Luippold

Keyword(s):

Cell Division ◽

Seed Germination ◽

Cell Expansion ◽

Lettuce Seed ◽

Lettuce Seed Germination

Download Full-text

Rice OsRAD21-2 is Expressed in Actively Dividing Tissues and its Ectopic Expression in Yeast Results in Aberrant Cell Division and Growth

Journal of Integrative Plant Biology ◽

10.1111/j.1744-7909.2010.01009.x ◽

2011 ◽

Vol 53 (1) ◽

pp. 14-24 ◽

Cited By ~ 5

Author(s):

Chunyan Gong ◽

Tang Li ◽

Qi Li ◽

Longfeng Yan ◽

Tai Wang

Keyword(s):

Cell Division ◽

Ectopic Expression ◽

Aberrant Cell

Download Full-text

Overexpression of lpxT Gene in Escherichia coli Inhibits Cell Division and Causes Envelope Defects without Changing the Overall Phosphorylation Level of Lipid A

Microorganisms ◽

10.3390/microorganisms8060826 ◽

2020 ◽

Vol 8 (6) ◽

pp. 826

Author(s):

Federica A. Falchi ◽

Flaviana Di Lorenzo ◽

Roberto Pizzoccheri ◽

Gianluca Casino ◽

Moira Paroni ◽

...

Keyword(s):

Escherichia Coli ◽

Cell Division ◽

Lipid A ◽

Cell Envelope ◽

Osmotic Shock ◽

Ectopic Expression ◽

Phenotypic Effect ◽

Osmotic Lysis ◽

Membrane Defects ◽

Inner Membrane Protein

LpxT is an inner membrane protein that transfers a phosphate group from the essential lipid undecaprenyl pyrophosphate (C-55PP) to the lipid A moiety of lipopolysaccharide, generating a lipid A tris-phosphorylated species. The protein is encoded by the non-essential lpxT gene, which is conserved in distantly related Gram-negative bacteria. In this work, we investigated the phenotypic effect of lpxT ectopic expression from a plasmid in Escherichia coli. We found that lpxT induction inhibited cell division and led to the formation of elongated cells, mostly with absent or altered septa. Moreover, the cells became sensitive to detergents and to hypo-osmotic shock, indicating that they had cell envelope defects. These effects were not due to lipid A hyperphosphorylation or C-55PP sequestering, but most likely to defective lipopolysaccharide transport. Indeed, lpxT overexpression in mutants lacking the L,D-transpeptidase LdtD and LdtE, which protect cells with outer membrane defects from osmotic lysis, caused cell envelope defects. Moreover, we found that pyrophosphorylated lipid A was also produced in a lpxT deletion mutant, indicating that LpxT is not the only protein able to perform such lipid A modification in E. coli.

Download Full-text