• The Korean Journal of Zoology
• /
• v.38 no.4
• /
• pp.550-556
• /
• 1995

The c-myc proto-oncogene is Involved In the control of normal cell proliferation and differentiation of many cell lineages. Although it has heen suggested that c-myc may play an important role in the mammalian early development, it Is unclear whether the embryonic c-myc mRNA is originated from zygotic gene expression or stored maternal message. Thus, we have construded expression vectors, In which the 5, flanking sequences including c-myc promoter region and a large non-coding exon I are fused 'sith E. coli lacZ gene that encedes $\beta$-galactosldase as a reporter. As c-myc exon I contains a modulatory sequence, we designed t, vo types of vectors (pcmyc.Gall and pcmyc-Ga12) to examine the role of exon I in c-myc expression. The former contains the complete exon I and the later has a deletion in 40 bp of modulator sequence located In the exon I of c-myc These vectors were microInjected into fertilized one-cell embryos and $\beta$-galactosidase activity was examined by X-gal staining during early embryogenesis. $\beta$-galactosidase activity derived from c-myc promoter was decreased at two-cell stage. The expression level directed by pcmyc- Ga12 was similar to that of pcmyc-Gal1, indicating that the medulatory sequence in exon I may not be Involved at least In the regulation of embryonic c-myc expression. In summary, the present study indicates that the c-myc promoter is functional at the early stage embryo, and the regulation of c-myc expression is under the control of "zygotic" clock of preimplantation mouse embryos.e embryos.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.6
• /
• pp.1024-1030
• /
• 1996

Capsaicin (8-methyl-N-vanillyl-6-nonenamide: CAP) is a mai or ingredient of hot pepper that has been used as a spicy food additive, preservative, and medicine. In this study, we evaluated the effect of dietary CAP on the selected proto-oncogene(c-jun, c-myc, H-ras, erbB, p53) expressions in various tissues of mice. Male ICR mice were divided into four groups and fed the experimental diets containing CAP at the levels of 0, 5, 20 and 100ppm for four weeks. Steady state RNA levels in various tissues were measured by slot blot hybridization assay. C-jun expression level was enhanced in stomach tissue from mice fed 20ppm CAP and significantly reduced from mice fed 100ppm CAP. The c-jun expression levels were differentially altered in organ-specific manner, Tumor suppressor gene p53 expression level appeared to be slightly increased in the liver from mice fed 20ppm CAP. These results suggested that dietary CAP differentially modulates c-jun and p53 expression in various organs.

• The Korean Journal of Zoology
• /
• v.38 no.2
• /
• pp.196-203
• /
• 1995

The c-myc proto-oncogene, one of the immediately earlY genes, is expressed in various mammalian cell types and heavily involved in the regulation of cell proliferation and differentiation. To determine endogeneous expression pattern of c-myc gene in preimpBantation mouse embwos, we employed a reverse transcription coupled to polvrnerase chain reaction (RT-PCR). Transcript of c-myc was detected at fertilized embryos as a maternal transcript. At the early two-cell stave, transcript of c-myc gene was hardly detected, bu, appeared at late two-cell embryos as a zygotic transcript. The level of c-myc expresion was increased at later stases and peaked at blastocvst stage. To examine the functional role of promoter region for c-myc gene transcription, we fused the 5'upstream region (1.8 kb) including econ 1 of c-myc genomic DNA with E. coli lacE gene fnamed as pcMYC-laczl. pcMYC-lacZ was microiniected into the pronscleus of mouse one-cell embryovs, and p·salactosidase activity was determined tv histochemical staining with X-gal at different stases. f-galactosidase activity was detected only at blastocyst, but not at the earlier stage embryos. This result indicates that c-myc gene is transcriptionallv active during mouse preimplantation development.

• Proceedings of the Zoological Society Korea Conference
• /
• 1996.04a
• /
• pp.44.1-44
• /
• 1996

No Abstract, See Full Text

• Molecules and Cells
• /
• v.20 no.2
• /
• pp.157-166
• /
• 2005

The c-myc proto-oncogene encodes a nuclear protein that is deregulated and/or mutated in most human cancers. Acting primarily as an activator and sometimes as a repressor, MYC protein controls the synthesis of up to 10-15% of genes. The key MYC targets contributing to oncogenesis are incompletely enumerated and it is not known whether pathology arises from the expression of physiologic targets at abnormal levels or from the pathologic response of new target genes that are not normally regulated by MYC. Regardless of which, available evidence indicates that the level of MYC expression is an important determinant of MYC biology. The c-myc promoter has architectural and functional features that contribute to uniform expression and help to prevent or mitigate conditions that might otherwise create noisy expression. Those features include the use of an expanded proximal promoter, the averaging of input from dozens of transcription factors, and real-time feedback using the supercoil-deformable Far UpStream Element (FUSE) as physical sensor of ongoing transcriptional activity, and the FUSE binding protein (FBP) as well as the FBP interacting repressor (FIR) as effectors to enforce normal transcription from the c-myc promoter.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 1998.07a
• /
• pp.32-33
• /
• 1998

생물체에서 유전외적 변형의 하나인 DNA 메틸화는 cis-acting factor의 조성변화를 통하여 세포특이 유전자의 발현과 virus latency, genomic imprinting, mutagenesis등과 같은 생물학적 효과를 나타내는 것으로 알려져 있다.(reviewed by Olle Heby, 1995). 5-azaCR, 5-azaCdR 그리고 6-azaCR의 처리결과는 배아자체의 DNA 메틸화의 유지가 정상발생에 필수적임을 알 수 있으며, 메틸화에 의한 배아발생 조절기작이 존재함을 암시하고 있다. 이러한 과정에서 5-azaCR과 5-azaCdR은 서로다른 경로를 통하여 배아발생에 관여함을 보여주었다. 즉, 5-azaCdR은 주로 DNA에 incorporation되어 작용하는 것으로 여겨지며, 5-azaCR은 DNA 보다는 RNA에 incorporation되어 작용하는 것으로 나타났다. 그리고, 비록 소수의 유전자만이 조사되었지만, 5-azaCdR의 incorporation에 의한 cis-acting factor의 변화는 전사인자인 c-myc proto-oncogene과 fluid 수송에 관여하는 $Na^{+}$, $K^{+}$-ATPase 유전자의 전사를 억제하지 않았다. 반면, 5-azaCR의 RNA로의 incorporation은 전사인자인 c-myc proto-oncogene의 전사를 억제하였으며, 연이어 fluid 수송에 관련되어있는 $Na^{+}$, $K^{+}$-ATPase 유전자의 전사를 억제하였다. 이것은 아마도 RNA로 incorporation된 5-azaCR은 RNA의 post-transcriptional processing에 영향을 주어 trans-acting factor의 조성을 변화, 전사적 repression을 유발한 것으로 사료된다. 생쥐 착상전 초기배아에서 DNA 메틸화는 short-term하게는 cis-acting factor로써 전사적 수준에서 유전자발현 조절하며, 그리고 유전자발현을 통하여 long-term하게는 배아발생에 관여 할 것이라고 사료된다.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.10
• /
• pp.5233-5236
• /
• 2012

CK2 is a serine threonine kinase that participates in a variety of cellular processes with more than 300 defined substrates. This critical enzyme is known to be upregulated in cancers, but the role of this upregulation in carcinogenesis is not yet fully understood but c-myc, one of the defined CK2 substrates, is a well-known proto-oncogene that is normally essential in developmental process but is also involved in tumor development. We evaluated the optimal enzyme and substrate concentrations for CK2 activity in both neoplastic and non-neoplastic human lung tissues using the c-$myc^{424-434}$ peptide (EQKLISEEDL) as a substrate. The activities measured for the neoplastic tissue were 600-750 U/mg protein while those for the control tissue was in the range of 650-800 U/mg. $K_m$ value for c-myc peptide was determined as $0.33{\mu}M$ in non-neoplastic tissue and $0.18{\mu}M$ in neoplastic tissue. In this study, we did not observe an increased activity in the neoplastic tissue when compared with the non-neoplastic lung tissue, but we recorded two times higher affinity for c-$myc^{424-434}$ in cancer tissue. Considering the metabolic position of c-$myc^{424-434}$, our results suggest that phosphorylation by CK2 may be important in dimerization and thus it might affect the regulation of c-myc in cancer tissues.

• BMB Reports
• /
• v.28 no.5
• /
• pp.414-419
• /
• 1995

The retroviruses carrying ${\nu}-myc$ and ${\nu}-raf$ oncogenes were infected into fetal thymic organ culture (FTOC) to study the molecular mechanisms involved in T cell development. T cell lymphomas in the different stages of T cell development were obtained from this culture system. Interestingly, a few cell lines obtained from this system have a lack of transfected oncogenes, however these cells have the characteristics of transformed cells. In spite of the discrete phenotype of these transformed cell lines, the same pattern of recombination of endogenous c-raf genes was detected from Southern blot analysis. We suggest in this regard that the translocation event of thymocytes, or abnormal promoter activity, can cause lymphomagenesis by way of c-raf.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.16
• /
• pp.7061-7069
• /
• 2015

Background: During the past decades, the incidence and mortality rate of stomach cancer has demonstrated a great decrease in the world, but it is still one of the most common and fatal cancers especially among men worldwide, including Iran. The MYC proto-oncogene, which is located at 8q24.1, regulates 15% of genes and is activated in 20% of all human tumors. MYC amplification and overexpression of its protein product has been reported in 15-30% of gastric neoplasias. The aim of this investigation was to find the relative efficacy of CISH (chromogenic in situ hybridization) or IHC (immunohistochemistry) in diagnosis and prognosis of gastric cancer, as well as the relationship of amplification and expression of C-MYC gene with patient survival. Materials and Methods: In this cross-sectional study, 102 samples of gastric cancer were collected from patients who had undergone primary surgical resection at the Cancer Institute Hospital, Tehran University of Medical Sciences, from July 2009 to March 2014. All samples were randomly selected from those who were diagnosed with gastric adenocarcinomas. CISH and IHC methods were performed on all of them. Results: Patients were classified into two groups. The first consisted of stage I and II cases, and the second of stage III and IV. Survival tests for both groups was carried out with referrnce to CISH test reults. Group II (stage III & IV) with CISH+ featured lower survival than those with CISH- (p=0.233), but group I (stage I & II) patients demonstrated no significant variation with CISH+ or CISH- (p=0.630). Kaplan-Meier for both groups was carried out with IHC test findings and showed similar results. This data revealed that both diffuse and intestinal types of gastric cancer occurred significantly more in men than women. Our data also showed that CISH+ patients (43%) were more frequent in comparison with IHC+ patients (14.7%). Conclusions: For planning treatment of gastric cancer patients, by focusing on expanding tumors, which is the greatest concern of the surgeons and patients, CISH is a better and more feasible test than IHC, in regard to sensitivity and specificity. Therefore, CISH can be used as a feasible test for tumor growth and prognosis in stage III and IV lesions. This study also indicated that C-MYC amplification in gastric cancer is correlated with survival in advanced stages.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.23 no.2
• /
• pp.71-84
• /
• 2010

Purpose: In the theory of traditional medicine, Glenditsia spina(GS) can resolve carbuncle, relive swelling, dispel wind and destroy parasites. This study was designed to investigate the effects of GS on gene expression of ovarian tissue in polycystic ovary syndrome(PCOS) rats. Methods: In this experiment, female rats injected with a single dose of 2 mg estradiol valerate(EV) and GS was given for 5 weeks. The genetic profile for the effects on ovarian tissue in PCOS rats was measured using microarray technique, and the functional analysis on these genes was conducted. Results: 985 genes were increased in control and restored to normal level in GS group. (B), 733 genes were decreased in control group and restored to normal level in GS group. (F). Metabolic pathways related in B group genes were Graft-versus-host disease, Allograft rejection, Autoimmune thyroid disease, Cytokine-cytokine receptor interaction, Small cell lung cancer, Type I diabetes mellitus. Metabolic pathways related in F group genes were Antigen processing and present, Adipocytokine signalling pathway, Focal adhesion, ECM-receptor interaction, Pancreatic cancer, Notch signalling pathway, Tight junction. The network of total protein interactions was measured using cytoscape program, and some key molecules, such as c-Fos, c-Myc, ABL1 related in B group, MAPK8, RASA1, CALR related in F group that can be used for elucidation of therapeutical mechanism of medicine in future were identified. Conclusion: These results suggest possibility of GS as anti-cancer and anti-hyperplasia drug in PCOS. In addition, the present author also suggests that related mechanisms are involved in suppression of proto-oncogene such as c-Fos, c-Myc and ABL1, and in regulation of cell cycle such as RASA1.