scholarly journals p100: A Novel Proliferation-Associated Nuclear Protein Specifically Restricted to Cell Cycle Phases S, G2 , and M

Blood ◽  
1997 ◽  
Vol 90 (1) ◽  
pp. 226-233 ◽  
Author(s):  
H.J. Heidebrecht ◽  
F. Buck ◽  
J. Steinmann ◽  
R. Sprenger ◽  
H.H. Wacker ◽  
...  

Abstract By immunization with nuclear lysates of L428 cells, we raised a monoclonal mouse antibody, Ki-S2 (IgG1 ). In Western blots, this antibody recognizes a nuclear antigen with an apparent molecular mass of 100 kD, termed p100. Protein sequencing of p100 showed that this is a hitherto unknown protein. Immunohistochemical examination of cryostat and paraffin sections of nearly all human tissue types and neoplasms showed that p100 was exclusively expressed in the nuclei of a fraction of proliferating cells. Cell sorting and fluorescence-activated cell sorting analysis of stimulated peripheral blood mononuclear cells showed that p100 was exclusively expressed in proliferating cells from the transition G1/S until the end of cytokinesis. During mitosis, this protein is strictly associated with the spindle pole and with the mitotic spindle, whereas during S and G2 , p100 is diffusely distributed throughout the cell nucleus. Immediately after completion of cytokinesis, p100 was rapidly degraded. In L428 cells, p100 is phosphorylated at least during mitosis. It has a turnover time of about 1 hour. Studies on routinely processed paraffin sections of specimens of malignant lymphoma, benign and malignant nevocellular tumors, and breast cancer showed that in all cases less than 40% of the Ki-67–positive growth fraction expressed p100. Thus, p100 might prove to be a more reliable measure of cellular proliferation and one that is more closely correlated to cancer prognosis, beyond its general biologic relevance as a cell cycle protein.

Blood ◽  
1997 ◽  
Vol 90 (1) ◽  
pp. 226-233 ◽  
Author(s):  
H.J. Heidebrecht ◽  
F. Buck ◽  
J. Steinmann ◽  
R. Sprenger ◽  
H.H. Wacker ◽  
...  

By immunization with nuclear lysates of L428 cells, we raised a monoclonal mouse antibody, Ki-S2 (IgG1 ). In Western blots, this antibody recognizes a nuclear antigen with an apparent molecular mass of 100 kD, termed p100. Protein sequencing of p100 showed that this is a hitherto unknown protein. Immunohistochemical examination of cryostat and paraffin sections of nearly all human tissue types and neoplasms showed that p100 was exclusively expressed in the nuclei of a fraction of proliferating cells. Cell sorting and fluorescence-activated cell sorting analysis of stimulated peripheral blood mononuclear cells showed that p100 was exclusively expressed in proliferating cells from the transition G1/S until the end of cytokinesis. During mitosis, this protein is strictly associated with the spindle pole and with the mitotic spindle, whereas during S and G2 , p100 is diffusely distributed throughout the cell nucleus. Immediately after completion of cytokinesis, p100 was rapidly degraded. In L428 cells, p100 is phosphorylated at least during mitosis. It has a turnover time of about 1 hour. Studies on routinely processed paraffin sections of specimens of malignant lymphoma, benign and malignant nevocellular tumors, and breast cancer showed that in all cases less than 40% of the Ki-67–positive growth fraction expressed p100. Thus, p100 might prove to be a more reliable measure of cellular proliferation and one that is more closely correlated to cancer prognosis, beyond its general biologic relevance as a cell cycle protein.


2010 ◽  
Vol 298 (6) ◽  
pp. R1615-R1626 ◽  
Author(s):  
Neil I. Bower ◽  
Ian A. Johnston

The mRNA expression of myogenic regulatory factors, including myoD1 (myoblast determination factor) gene paralogs, and their regulation by amino acids and insulin-like growth factors were investigated in primary cell cultures isolated from fast myotomal muscle of Atlantic salmon ( Salmo salar). The cell cycle and S phase were determined as 28.1 and 13.3 h, respectively, at 18°C. Expression of myoD1b and myoD1c peaked at 8 days of culture in the initial proliferation phase and then declined more than sixfold as cells differentiated and was correlated with PCNA (proliferating cell nuclear antigen) expression ( R = 0.88, P < 0.0001; R = 0.70, P < 0.0001). In contrast, myoD1a transcripts increased from 2 to 8 days and remained at elevated levels as myotubes were formed. mRNA levels of myoD1c were, on average, 3.1- and 5.7-fold higher than myoD1a and myoD1b, respectively. Depriving cells of amino acids and serum led to a rapid increase in pax7 and a decrease in myoD1c and PCNA expression, indicating a transition to a quiescent state. In contrast, amino acid replacement in starved cells produced significant increases in myoD1c (at 6 h), PCNA (at 12 h), and myoD1b (at 24 h) and decreases in pax7 expression as cells entered the cell cycle. Our results are consistent with temporally distinct patterns of myoD1c and myoD1b expression at the G1 and S/G2 phases of the cell cycle. Treatment of starved cells with insulin-like growth factor I or II did not alter expression of the myoD paralogs. It was concluded that, in vitro, amino acids alone are sufficient to stimulate expression of genes regulating myogenesis in myoblasts involving autocrine/paracrine pathways. The differential responses of myoD paralogs during myotube maturation and amino acid treatments suggest that myoD1b and myoD1c are primarily expressed in proliferating cells and myoD1a in differentiating cells, providing evidence for their subfunctionalization following whole genome and local duplications in the Atlantic salmon lineage.


1992 ◽  
Vol 102 (1) ◽  
pp. 71-78 ◽  
Author(s):  
SANDRA CITTERIO ◽  
SERGIO SGORBATI ◽  
MARISA LEVI ◽  
BRUNO MARIA COLOMBO ◽  
ELIO SPARVOLI

The identification of cell proliferation markers has been shown to be a useful tool with which to study basic mechanisms of cell cycle progression. The use of immunofluorescence techniques revealed the presence of the proliferating cell nuclear antigen (PCNA) in pea tissue, where we observed a high PCNA expression in proliferating cells of the root meristem compared to noncycling cells of the differentiated leaf. The presence of PCNA was monitored also during the time-course of seed germination, before, during and after the cell cycle resumption of the embryo cells. PCNA is present in embryo cells not only during and after resumption of the cell cycle but also before, when cells have not yet begun replicating their genome. A bivariate flow cytometric analysis of DNA and nuclear protein content was used to localize precisely the cells of the examined pea tissues in different cell cycle phase subcompartments. A high correlation was found between the degree of cell proliferation and the protein content of G1 nuclei, on the one hand, and the percentage of PCNA positive cells on the other.


2001 ◽  
Vol 359 (2) ◽  
pp. 361-367 ◽  
Author(s):  
Elizabeth J. FOX ◽  
Stephanie C. WRIGHT

The Myc/Max/Mad transcription factor network plays a central role in the control of cellular proliferation, differentiation and apoptosis. In order to elucidate the biological function of Mad3, we have analysed the precise temporal patterns of Mad3 mRNA expression during the cell cycle and differentiation in cultured cells. We show that Mad3 is induced at the G1/S transition in proliferating cells; expression persists throughout S-phase, and then declines as cells pass through G2 and mitosis. The expression pattern of Mad3 is coincident with that of Cdc2 throughout the cell cycle. In contrast, the expression of Mad3 during differentiation of cultured mouse erythroleukemia cells shows two transient peaks of induction. The first of these occurs at the onset of differentiation, and does not correlate with the S-phase of the cell cycle, whereas the second is coincident with the S-phase burst that precedes the terminal stages of differentiation. Our results therefore suggest that Mad3 serves a cell-cycle-related function in both proliferating and differentiating cells, and that it may also have a distinct role at various stages of differentiation.


2004 ◽  
Vol 24 (12) ◽  
pp. 5404-5420 ◽  
Author(s):  
Steven P. Angus ◽  
Christopher N. Mayhew ◽  
David A. Solomon ◽  
Wesley A. Braden ◽  
Michael P. Markey ◽  
...  

ABSTRACT The retinoblastoma (RB) tumor suppressor is a critical negative regulator of cellular proliferation. Repression of E2F-dependent transcription has been implicated as the mechanism through which RB inhibits cell cycle progression. However, recent data have suggested that the direct interaction of RB with replication factors or sites of DNA synthesis may contribute to its ability to inhibit S phase. Here we show that RB does not exert a cis-acting effect on DNA replication. Furthermore, the localization of RB was distinct from replication foci in proliferating cells. While RB activation strongly attenuated the RNA levels of multiple replication factors, their protein expression was not diminished coincident with cell cycle arrest. During the first 24 h of RB activation, components of the prereplication complex, initiation factors, and the clamp loader complex (replication factor C) remained tethered to chromatin. In contrast, the association of PCNA and downstream components of the processive replication machinery was specifically disrupted. This signaling from RB occurred in a manner dependent on E2F-mediated transcriptional repression. Following long-term activation of RB, we observed the attenuation of multiple replication factors, the complete cessation of DNA synthesis, and impaired replicative capacity in vitro. Therefore, functional distinctions exist between the “chronic” RB-mediated arrest state and the “acute” arrest state. Strikingly, attenuation of RB activity reversed both acute and chronic replication blocks. Thus, continued RB action is required for the maintenance of two kinetically and functionally distinct modes of replication inhibition.


1999 ◽  
Vol 11 (1) ◽  
pp. 31 ◽  
Author(s):  
Noriyuki Takai ◽  
Jun Yoshimatsu ◽  
Yoshihiro Nishida ◽  
Isao Miyakawa ◽  
Ryoji Hamanaka ◽  
...  

The polo-like kinase (PLK) is a mammalian serine/threonine kinase involved in cell cycle regulation. Much evidence for the role of PLK in the cell cycle has come from studies of cultured cells; however, little is known about its function or even expression in vivo . The present study examined the features of PLK expression in the mouse placenta and ovary. Immunohistochemical studies showed that PLK is highly expressed in the basement membrane of the endometrial gland, in some endothelial cells, in endometrium after embryo implantation, in trophoblastic tissue invading the decidua, in the ovarian stroma and in some lutein bodies. In contrast, PLK was not detectable by immunohistochemistry in endometrial stroma before decidualization, in decidua, in trophoblastic tissue not invading the decidua or in ovarian follicles. PLK expression seemed to be correlated with the expression of proliferation cellular nuclear antigen (PCNA) in many placental and ovarian cells, reflecting a role in cellular proliferation. Nevertheless, in ovarian stroma and lutein bodies where PCNA was not expressed, PLK was strongly expressed. This finding indicates that PLK may have some post mitotic functions in certain specialized cell types.


Reproduction ◽  
2009 ◽  
Vol 137 (4) ◽  
pp. 699-707 ◽  
Author(s):  
Anna T Grazul-Bilska ◽  
Joel S Caton ◽  
Wendy Arndt ◽  
Kelly Burchill ◽  
Clayton Thorson ◽  
...  

Sheep were fed a maintenance (M) diet with adequate (A) Se or high (H) Se concentration from 21 days before breeding to day 135 of pregnancy. From day 50 to day 135 of pregnancy (tissue collection day), a portion of the ewes from ASe and HSe groups were fed restricted (R; 60% of M) diet. Fetal ovarian sections were stained for: 1) the presence of proliferating cell nuclear antigen (a marker of proliferating cells) to determine the proportion of proliferating primordial follicles, or the labeling index (LI; percentage of proliferating cells) for primordial, primary, secondary and antral follicles, stromal tissues, and blood vessels; 2) factor VIII (a marker of endothelial cells) or 3) a presence of apoptotic cells/bodies. The number of proliferating primordial follicles and the LI of primordial follicles was decreased by R and/or HSe diets. The LI was similar for theca and granulosa cells, and for secondary or antral follicles, but was greater in secondary and antral than in primordial and primary follicles. R diet and/or Se affected the LI in all follicle types, in stromal tissues and blood vessels. A dense network of blood vessels was detected in the areas containing secondary to antral follicles, medulla, and hilus, but areas containing primordial follicles were poorly vascularized. The number of apoptotic cells was minimal. These results demonstrate that nutrient restriction and/or Se level in the maternal diet affected cellular proliferation in follicles, blood vessels, and stromal tissues in fetal ovaries. Thus, plane of nutrition and Se in the maternal diet may impact fetal ovarian development and function.


1989 ◽  
Vol 75 (6) ◽  
pp. 557-562 ◽  
Author(s):  
Sergio Crispino ◽  
Ambrogio Brenna ◽  
Daniela Colombo ◽  
Bajardo Flores ◽  
Silvestro D'Amico ◽  
...  

Measurements of cell cycle kinetics have been found to correlate with the clinical course of patients with breast cancer. However, the thymidine labeling index and more rapid methods like flow cytometry remain complicated and costly. We assessed cell proliferation of 67 breast carcinomas by an immunoperoxidase procedure using a monoclonal antibody, Ki-67, which reacts with a nuclear antigen in proliferating cells. The percentage of Ki-67 positive cells ranged from 2% to 70 %. Tumors with high mitotic rate, high nuclear grade, high histologic grade, and negative estrogen receptors had statistically higher Ki-67 labeling rates. We found no significant differences between the Ki-67 labeling rate and other clinical (age at diagnosis, menopausal status) or pathologic (necrosis, fibrosis, vascular invasion, lymphatic invasion, cellular reaction, tumor size, lymph node metastases) features assessed. These results parallel previously reported data, and confirm that this immunohistochemical staining of breast carcinoma by Ki-67 monoclonal antibody can be considered a rapid and convenient method for assessing cell cycle kinetics. However, further studies, evaluating the correlation between Ki-67 labeling rate and prognosis are needed to better define the real usefulness of this analysis in clinical practice.


1994 ◽  
Vol 6 (4) ◽  
pp. 453-457 ◽  
Author(s):  
Alain Pierre Théon ◽  
Loretta Metzger ◽  
Stephen Griffey

Cell proliferation in canine, feline, and equine tumors was evaluated using immunohistochemical detection of in vitro 5–bromodeoxyuridine (BrdU) incorporation, proliferating cell nuclear antigen (PCNA), and interchromatin-associated antigen (p105). Ten tumors in each species were analyzed. The tumor proliferative fraction (PF) was defined as the percentage of labeled nuclei for 5,000 tumor nuclei counted. Immunoreactivity was observed with all techniques in all species. A good correlation was observed between the proliferative fractions measured with the BrdU (PFBrdU) and PCNA (PFPCNA) techniques ( rs = 0.523, P = 0.0026). There was no correlation between the PFs measured with the BrdU (PFBrdU) and p105 (PFP105) techniques. Using the median values obtained from the different approaches as cutoff points to define slowly and rapidly proliferating tumors, there was an 80% agreement ( P = 0.009) between PFBrdU and PFPCNA and no agreement between PFBrdU and PFP105 The results of this study indicate that both BrdU and PCNA labeling methods can be used reliably for identifying proliferating cells in animal tumors. In addition, PCNA could be used to replace the BrdU method to assess tumor proliferative fraction because it does not require pretreatment of tissues.


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