scholarly journals Tight association of autophagy and cell cycle in leukemia cells

2021 ◽  
Author(s):  
Alena Gschwind ◽  
Christian Marx ◽  
Marie D. Just ◽  
Paula Severin ◽  
Hannah Behring ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Sorting ◽  
G1 Phase ◽  
Cycle Phase ◽  
Cell Populations ◽  
Flux Analysis ◽  
Double Labeling ◽  
Flow Cytometric ◽  
Sorting Technique ◽  
M Phase

Abstract BackgroundAutophagy plays an essential role in maintaining cellular homeostasis and in the response to cellular stress. Autophagy is also involved in cell cycle progression, yet the relationship between these processes is not clearly defined.ResultsIn exploring this relationship, we observed that the inhibition of autophagy impaired the G2/M phase-arresting activity of etoposide but enhanced the G1 phase-arresting activity of palbociclib. We further investigated the connection of basal autophagy and cell cycle by utilizing the autophagosome tracer dye Cyto-ID in two ways. First, we established a double-labeling flow-cytometric procedure with Cyto-ID and the DNA probe DRAQ5, permitting the cell cycle phase-specific determination of autophagy in live cells. This approach demonstrated that different cell cycle phases were associated with different autophagy levels: G1 phase cells had the lowest one and G2/M phase cells had the highest one. Second, we developed a flow-cytometric cell sorting procedure based on Cyto-ID that separates cell populations into fractions with low, medium and high autophagy. Cell cycle analysis of Cyto-ID-sorted cells confirmed that the high autophagy fraction contained a much higher percentage of G2/M phase cells than the low autophagy fraction. Beyond that, Cyto-ID-based cell sorting proved also to be useful for assessing other autophagy-related processes: extracellular flux analysis revealed metabolic differences between the cell populations, with higher autophagy being associated with higher respiration, higher mitochondrial ATP production and higher glycolysis.ConclusionThis work sheds new light on the interrelation of autophagy and cell cycle by establishing a novel cell sorting technique based on Cyto-ID.

scholarly journals Cell cycle regulation of thymidine kinase: residues near the carboxyl terminus are essential for the specific degradation of the enzyme at mitosis.

1991 ◽  
Vol 11 (5) ◽  
pp. 2538-2546 ◽  
Author(s):  
M G Kauffman ◽  
T J Kelly
Keyword(s):  
Cell Cycle ◽  
Amino Acids ◽  
Thymidine Kinase ◽  
Cell Cycle Regulation ◽  
Carboxyl Terminus ◽  
G1 Phase ◽  
Cycle Phase ◽  
M Phase ◽  
Specific Degradation ◽  
Cycle Regulation

The level of human thymidine kinase (TK) polypeptide is subject to cell cycle regulation. The enzyme is barely detectable in G1 phase but increases 10- to 20-fold by M phase. The low level of human TK in G1 phase is due primarily to the specific degradation of the protein during cell division. Substitution of heterologous promoters, removal of the introns, and deletion of all of the 3' untranslated region from the human TK gene do not affect cell cycle regulation of the enzyme. However, deletion of the carboxyl-terminal 40 amino acids or fusion of beta-galactosidase to the carboxyl terminus of human TK completely abolishes cell cycle regulation and stabilizes the protein throughout the cell cycle. These alterations do not significantly alter the specific enzymatic activity of TK. Changing the carboxyl terminus or deletion of the last 10 amino acids does not alter cell cycle regulation. These data demonstrate that residues near the carboxyl terminus of TK are essential for the cell cycle phase-specific degradation of the enzyme.

Cell cycle regulation of thymidine kinase: residues near the carboxyl terminus are essential for the specific degradation of the enzyme at mitosis

1991 ◽  
Vol 11 (5) ◽  
pp. 2538-2546
Author(s):  
M G Kauffman ◽  
T J Kelly
Keyword(s):  
Cell Cycle ◽  
Amino Acids ◽  
Thymidine Kinase ◽  
Cell Cycle Regulation ◽  
Carboxyl Terminus ◽  
G1 Phase ◽  
Cycle Phase ◽  
M Phase ◽  
Specific Degradation ◽  
Cycle Regulation

The level of human thymidine kinase (TK) polypeptide is subject to cell cycle regulation. The enzyme is barely detectable in G1 phase but increases 10- to 20-fold by M phase. The low level of human TK in G1 phase is due primarily to the specific degradation of the protein during cell division. Substitution of heterologous promoters, removal of the introns, and deletion of all of the 3' untranslated region from the human TK gene do not affect cell cycle regulation of the enzyme. However, deletion of the carboxyl-terminal 40 amino acids or fusion of beta-galactosidase to the carboxyl terminus of human TK completely abolishes cell cycle regulation and stabilizes the protein throughout the cell cycle. These alterations do not significantly alter the specific enzymatic activity of TK. Changing the carboxyl terminus or deletion of the last 10 amino acids does not alter cell cycle regulation. These data demonstrate that residues near the carboxyl terminus of TK are essential for the cell cycle phase-specific degradation of the enzyme.

scholarly journals Posttranslational Phosphorylation and Ubiquitination of the Saccharomyces cerevisiae Poly(A) Polymerase at the S/G2 Stage of the Cell Cycle

2000 ◽  
Vol 20 (8) ◽  
pp. 2794-2802 ◽  
Author(s):  
Neptune Mizrahi ◽  
Claire Moore
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Sorting ◽  
S Phase ◽  
Phase Arrest ◽  
Phosphatase Treatment ◽  
M Phase ◽  
64 Kda Protein ◽  
Mitotic Phosphorylation ◽  
Cycle Regulation

ABSTRACT The poly(A) polymerase of the budding yeast Saccharomyces cerevisiae (Pap1) is a 64-kDa protein essential for the maturation of mRNA. We have found that a modified Pap1 of 90 kDa transiently appears in cells after release from α-factor-induced G1 arrest or from a hydroxyurea-induced S-phase arrest. While a small amount of modification occurs in hydroxyurea-arrested cells, fluorescence-activated cell sorting analysis and microscopic examination of bud formation indicate that the majority of modified enzyme is found at late S/G2 and disappears by the time cells have reached M phase. The reduction of the 90-kDa product upon phosphatase treatment indicates that the altered mobility is due to phosphorylation. A preparation containing primarily the phosphorylated Pap1 has no poly(A) addition activity, but this activity is restored by phosphatase treatment. A portion of Pap1 is also polyubiquitinated concurrent with phosphorylation. However, the bulk of the 64-kDa Pap1 is a stable protein with a half-life of 14 h. The timing, nature, and extent of Pap1 modification in comparison to the mitotic phosphorylation of mammalian poly(A) polymerase suggest an intriguing difference in the cell cycle regulation of this enzyme in yeast and mammalian systems.

scholarly journals Fluctuation in radioresponse of HeLa cells during the cell cycle evaluated based on micronucleus frequency

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroaki Shimono ◽  
Atsushi Kaida ◽  
Hisao Homma ◽  
Hitomi Nojima ◽  
Yusuke Onozato ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Hela Cells ◽  
Time Lapse ◽  
S Phase ◽  
G1 Phase ◽  
M Phase ◽  
G2 Phase ◽  
The Difference ◽  
Time Lapse Imaging ◽  
First Time

AbstractIn this study, we examined the fluctuation in radioresponse of HeLa cells during the cell cycle. For this purpose, we used HeLa cells expressing two types of fluorescent ubiquitination-based cell cycle indicators (Fucci), HeLa-Fucci (CA)2 and HeLa-Fucci (SA), and combined this approach with the micronucleus (MN) assay to assess radioresponse. The Fucci system distinguishes cell cycle phases based on the colour of fluorescence and cell morphology under live conditions. Time-lapse imaging allowed us to further identify sub-positions within the G1 and S phases at the time of irradiation by two independent means, and to quantitate the number of MNs by following each cell through M phase until the next G1 phase. Notably, we found that radioresponse was low in late G1 phase, but rapidly increased in early S phase. It then decreased until late S phase and increased in G2 phase. For the first time, we demonstrated the unique fluctuation of radioresponse by the MN assay during the cell cycle in HeLa cells. We discuss the difference between previous clonogenic experiments using M phase-synchronised cell populations and ours, as well as the clinical implications of the present findings.

scholarly journals Heterogeneous Nuclear Ribonucleoprotein C Modulates Translation of c-myc mRNA in a Cell Cycle Phase-Dependent Manner

2003 ◽  
Vol 23 (2) ◽  
pp. 708-720 ◽  
Author(s):  
Jong Heon Kim ◽  
Ki Young Paek ◽  
Kobong Choi ◽  
Tae-Don Kim ◽  
Bumsuk Hahm ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Phase ◽  
In Vitro Translation ◽  
Cycle Phase ◽  
Dependent Manner ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
M Phase ◽  
Hnrnp C ◽  
A Cell ◽  
Nuclear Ribonucleoprotein

ABSTRACT The c-myc proto-oncogene plays a key role in the proliferation, differentiation, apoptosis, and regulation of the cell cycle. Recently, it was demonstrated that the 5′ nontranslated region (5′ NTR) of human c-myc mRNA contains an internal ribosomal entry site (IRES). In this study, we investigated cellular proteins interacting with the IRES element of c-myc mRNA. Heterogeneous nuclear ribonucleoprotein C (hnRNP C) was identified as a cellular protein that interacts specifically with a heptameric U sequence in the c-myc IRES located between two alternative translation initiation codons CUG and AUG. Moreover, the addition of hnRNP C1 in an in vitro translation system enhanced translation of c-myc mRNA. Interestingly, hnRNP C was partially relocalized from the nucleus, where most of the hnRNP C resides at interphase, to the cytoplasm at the G2/M phase of the cell cycle. Coincidently, translation mediated through the c-myc IRES was increased at the G2/M phase when cap-dependent translation was partially inhibited. On the other hand, a mutant c-myc mRNA lacking the hnRNP C-binding site, showed a decreased level of translation at the G2/M phase compared to that of the wild-type message. Taken together, these findings suggest that hnRNP C, via IRES binding, modulates translation of c-myc mRNA in a cell cycle phase-dependent manner.

Decitabine induces cell cycle arrest at the G1 phase via p21WAF1 and the G2/M phase via the p38 MAP kinase pathway

2003 ◽  
Vol 27 (11) ◽  
pp. 999-1007 ◽  
Author(s):  
Donald Lavelle ◽  
Joseph DeSimone ◽  
Maria Hankewych ◽  
Tatiana Kousnetzova ◽  
Yi-Hsiang Chen
Keyword(s):  
Cell Cycle ◽  
Map Kinase ◽  
Cell Cycle Arrest ◽  
P38 Map Kinase ◽  
G1 Phase ◽  
Cycle Arrest ◽  
M Phase ◽  
Map Kinase Pathway ◽  
Kinase Pathway

scholarly journals Flow cytometric identification of proliferative subpopulations within normal human epidermis and the localization of the primary hyperproliferative population in psoriasis.

1993 ◽  
Vol 178 (4) ◽  
pp. 1271-1281 ◽  
Author(s):  
Z Bata-Csorgo ◽  
C Hammerberg ◽  
J J Voorhees ◽  
K D Cooper
Keyword(s):  
Cell Cycle ◽  
Human Epidermis ◽  
Optical Characteristics ◽  
Small Cells ◽  
Nuclear Antigen ◽  
Quiescent State ◽  
Flow Cytometric ◽  
M Phase ◽  
Normal Human ◽  
Normal Epidermis

In this study we define the proliferative compartments of in vivo human epidermis, using specific antibodies related to cell differentiation (beta 1 and beta 4 integrins and K1/K10 differentiation keratins) and cell cycle (proliferating cell nuclear antigen [PCNA]) in combination with flow cytometric quantitation of the DNA content and optical characteristics of the cells. The beta 1 integrin (CD29) marked both of the potentially proliferative subsets in normal epidermis. One subset of normal epidermis is CD29+ K1/K10-, which was predominantly basal, and found to be comprised of slow cycling, small cells with primitive cytoplasmic organization. The vast majority (95.5%) of these cells were in a quiescent state (G0/early G1) as indicated by their lack of the cyclin, PCNA. The other proliferative subset of normal epidermis was CD29+ K1/K10+, which was suprabasal and occasional basal, highly proliferative, larger in size, and which exhibited a more complex cytoplasmic structure. Because early differentiation (K1/K10 expression) has begun in the CD29+ K1/K10+ subset, it is highly likely that they represent the proliferative population which is capable of transiently amplifying itself before terminal differentiation. Within lesional psoriatic epidermis, similar proliferative cell populations were present as in normal epidermis, and the hyperproliferative defect was localized to the beta 1 and beta 4 integrin+, K1/K10- populations, which in normal epidermis is basally located and quiescent with regard to cell cycle. In psoriatic epidermis, a six- to sevenfold increase in the number of cells in the S/G2+M phase of cell cycle was found among CD29+ K1/K10- cells (p < 0.05). Furthermore, all lesional K1/K10- cells showed high PCNA positivity, indicating that all these cells had been recently induced into cell cycle. By contrast, the proportion of cycling cells among lesional psoriatic CD29+ K1/K10+ keratinocytes was similar to normals. Anti-HLA-DR, CD45, and vimentin antibodies were used to concomitantly track the proliferative states of Langerhans cell, melanocyte, and infiltrating leukocyte populations. In normal epidermis, the cycling fractions (cells in S/G2/M phase) of these cells were similar to the CD29+K1/K10- keratinocytes, whereas in lesional epidermis their cycling pools were increased relative to normal, but not so much as the proliferative fractions of psoriatic CD29+ K1/K10- keratinocytes. These data demonstrate the use of simultaneous analysis of integrin expression, differentiation keratins, cyclin, cell cycle status, and optical characteristics of freshly isolated human epidermal cells. Such analysis allowed the physical identification and quantification of cy cling populations in normal human skin, and has enabled the precise location of the primary epidermal proliferative defect in psoriasis.

scholarly journals Estrogen Receptor Beta Displays Cell Cycle-Dependent Expression and Regulates the G1 Phase through a Non-Genomic Mechanism in Prostate Carcinoma Cells

2008 ◽  
Vol 30 (4) ◽  
pp. 349-365 ◽  
Author(s):  
Antoni Hurtado ◽  
Tomàs Pinós ◽  
Anna Barbosa-Desongles ◽  
Sandra López-Avilés ◽  
Jordi Barquinero ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Estrogen Receptor ◽  
Estrogen Receptor Beta ◽  
Mechanisms Of Action ◽  
S Phase ◽  
G1 Phase ◽  
Over Expression ◽  
M Phase ◽  
Receptor Beta

Background: It is well known that estrogens regulate cell cycle progression, but the specific contributions and mechanisms of action of the estrogen receptor beta (ERβ) remain elusive.Methods: We have analyzed the levels of ERβ1 and ERβ2 throughout the cell cycle, as well as the mechanisms of action and the consequences of the over-expression of ERβ1 in the human prostate cancer LNCaP cell line.Results: Both ERβ1 mRNA and protein expression increased from the G1 to the S phase and decreased before entering the G2/M phase, whereas ERβ2 levels decreased during the S phase and increased in the G2/M phase. ERβ1 protein was detected in both the nuclear and non-nuclear fractions, and ERβ2 was found exclusively in the nucleus. Regarding the mechanisms of action, endogenous ERβ was able to activate transcription via ERE during the S phase in a ligand-dependent manner, whereas no changes in AP1 and NFκB transactivation were observed after exposure to estradiol or the specific inhibitor ICI 182,780. Over-expression of either wild type ERβ1 or ERβ1 mutated in the DNA-binding domain caused an arrest in early G1. This arrest was accompanied by the interaction of over-expressed ERβ1 with c-Jun N-terminal protein kinase 1 (JNK1) and a decrease in c-Jun phosphorylation and cyclin D1 expression. The administration of ICI impeded the JNK1–ERβ1 interaction, increased c-Jun phosphorylation and cyclin D1 expression and allowed the cells to progress to late G1, where they became arrested.Conclusions: Our results demonstrate that, in LNCaP prostate cancer cells, both ERβ isoforms are differentially expressed during the cell cycle and that ERβ regulates the G1 phase by a non-genomic mechanism.

scholarly journals Isolation and Characterization of Highly Pure Type A Spermatogonia From Sterlet (Acipenser ruthenus) Using Flow-Cytometric Cell Sorting

2021 ◽  
Vol 9 ◽  
Author(s):  
Xuan Xie ◽  
Tomáš Tichopád ◽  
Galina Kislik ◽  
Lucie Langerová ◽  
Pavel Abaffy ◽  
...  
Keyword(s):  
Germ Cells ◽  
Cell Sorting ◽  
Developmental Stages ◽  
Type A ◽  
Cell Populations ◽  
Forward Scatter ◽  
Flow Cytometric ◽  
Flow Cytometric Cell ◽  
Type A Spermatogonia

Sturgeons are among the most ancient linages of actinopterygians. At present, many sturgeon species are critically endangered. Surrogate production could be used as an affordable and a time-efficient method for endangered sturgeons. Our study established a method for identifying and isolating type A spermatogonia from different developmental stages of testes using flow cytometric cell sorting (FCM). Flow cytometric analysis of a whole testicular cell suspension showed several well-distinguished cell populations formed according to different values of light scatter parameters. FCM of these different cell populations was performed directly on glass slides for further immunocytochemistry to identify germ cells. Results showed that the cell population in gate P1 on a flow cytometry plot (with high forward scatter and high side scatter parameter values) contains the highest amount of type A spermatogonia. The sorted cell populations were characterized by expression profiles of 10 germ cell specific genes. The result confirmed that setting up for the P1 gate could precisely sort type A spermatogonia in all tested testicular developmental stages. The P2 gate, which was with lower forward scatter and side scatter values mostly, contained type B spermatogonia at a later maturing stage. Moreover, expressions of plzf, dnd, boule, and kitr were significantly higher in type A spermatogonia than in later developed germ cells. In addition, plzf was firstly found as a reliable marker to identify type A spermatogonia, which filled the gap of identification of spermatogonial stem cells in sterlet. It is expected to increase the efficiency of germ stem cell culture and transplantation with plzf identification. Our study thus first addressed a phenotypic characterization of a pure type A spermatogonia population in sterlet. FCM strategy can improve the production of sturgeons with surrogate broodstock and further the analysis of the cellular and molecular mechanisms of sturgeon germ cell development.

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