Identification and expression analysis of R2R3-MYB gene family in Andrographis paniculata / 中国中药杂志

The plant growth, development, and secondary metabolism are regulated by R2 R3-MYB transcription factors. This study identified the R2 R3-MYB genes in the genome of Andrographis paniculata and analyzed the chromosomal localization, gene structure, and conserved domains, phylogenetic relationship, and promoter cis-acting elements of these R2 R3-MYB genes. Moreover, the gene expression profiles of R2 R3-MYB genes under abiotic stress and hormone treatments were generated by RNA-seq and validated by qRT-PCR. The results showed that A. paniculata contained 73 R2 R3-MYB genes on 21 chromosomes. These members belonged to 34 subfamilies, 19 of which could be classified into the known subfamilies in Arabidopsis thaliana. The 73 R2 R3-MYB members included 36 acidic proteins and 37 basic proteins, with the lengths of 148-887 aa. The domains, motifs, and gene structures of R2 R3-MYBs in A. paniculata were conserved. The promoter regions of these genes contains a variety of cis-acting elements related to the responses to environmental factors and plant hormones including light, ABA, MeJA, and drought. Based on the similarity of functions of R2 R3-MYBs in the same subfamily and the transcription profiles, ApMYB13/21/35/67/73(S22) may regulate drought stress through ABA pathway; ApMYB20(S11) and ApMYB55(S2) may play a role in the response of A. paniculata to high temperature and UV-C stress; ApMYB5(S7) and ApMYB33(S20) may affect the accumulation of andrographolide by regulating the expression of key enzymes in the MEP pathway. This study provides theoretical reference for further research on the functions of R2 R3-MYB genes in A. paniculata and breeding of A. paniculata varieties with high andrographolide content.

Identification and expression profiling of R2R3-MYB transcription factors in Erigeron breviscapus / 中国中药杂志

R2 R3-MYB transcription factors are ubiquitous in plants, playing a role in the regulation of plant growth, development, and secondary metabolism. In this paper, the R2 R3-MYB transcription factors were identified by bioinformatics analysis of the genomic data of Erigeron breviscapus, and their gene sequences, structures, physical and chemical properties were analyzed. The functions of R2 R3-MYB transcription factors were predicted by cluster analysis. Meanwhile, the expression patterns of R2 R3-MYB transcription factors in response to hormone treatments were analyzed. A total of 108 R2 R3-MYB transcription factors, named EbMYB1-EbMYB108, were identified from the genome of E. breviscapus. Most of the R2 R3-MYB genes carried 2-4 exons. The phylogenetic tree of MYBs in E. breviscapus and Arabidopsis thaliala was constructed, which classified 234 MYBs into 30 subfamilies. The MYBs in the five MYB subfamilies of A.thaliala were clustered into independent clades, and those in E. breviscapus were clustered into four clades. The transcriptome data showed that MYB genes were differentially expressed in different tissues of E. breviscapus and in response to the treatments with exogenous hormones such as ABA, SA, and GA for different time. The transcription of 13 R2 R3-MYB genes did not change significantly, and the expression patterns of some genes were up-regulated or down-regulated with the extension of hormone treatment time. This study provides a theoretical basis for revealing the mechanisms of R2 R3-MYB transcription factors in regulating the growth and development, stress(hormone) response, and active ingredient accumulation in E. breviscapus.

Molecular Testing of Brain Tumor

The World Health Organization (WHO) classification of central nervous system (CNS) tumors was revised in 2016 with a basis on the integrated diagnosis of molecular genetics. We herein provide the guidelines for using molecular genetic tests in routine pathological practice for an accurate diagnosis and appropriate management. While astrocytomas and IDH-mutant (secondary) glioblastomas are characterized by the mutational status of IDH, TP53, and ATRX, oligodendrogliomas have a 1p/19q codeletion and mutations in IDH, CIC, FUBP1, and the promoter region of telomerase reverse transcriptase (TERTp). IDH-wildtype (primary) glioblastomas typically lack mutations in IDH, but are characterized by copy number variations of EGFR, PTEN, CDKN2A/B, PDGFRA, and NF1 as well as mutations of TERTp. High-grade pediatric gliomas differ from those of adult gliomas, consisting of mutations in H3F3A, ATRX, and DAXX, but not in IDH genes. In contrast, well-circumscribed low-grade neuroepithelial tumors in children, such as pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and ganglioglioma, often have mutations or activating rearrangements in the BRAF, FGFR1, and MYB genes. Other CNS tumors, such as ependymomas, neuronal and glioneuronal tumors, embryonal tumors, meningothelial, and other mesenchymal tumors have important genetic alterations, many of which are diagnostic, prognostic, and predictive markers and therapeutic targets. Therefore, the neuropathological evaluation of brain tumors is increasingly dependent on molecular genetic tests for proper classification, prediction of biological behavior and patient management. Identifying these gene abnormalities requires cost-effective and high-throughput testing, such as next-generation sequencing. Overall, this paper reviews the global guidelines and diagnostic algorithms for molecular genetic testing of brain tumors.

Expression of c-myc and c-myb gene in leukemic bone marrow stromal cells and their correlation / 中国实验血液学杂志

This study was purposed to investigate the expression level of oncogene c-myc and c-myb in leukemic cells and leukemic bone marrow stromal cells (BMSC) and the correlation with each other. The expression levels of c-myc and c-myb in those cells were examined semi-quantitatively by reverse transcription polymerase chain reaction (RT-PCR). Flow cytometry analysis was used to detect the membrane surface antigens of leukemic cells and BMSC. The karyotype was analyzed by G-banding techniques. The results showed that (1) c-myc and c-myb gene were expressed in the normal control group, the leukemic cells and BMSC of patients group. The mean expression levels of c-myb mRNA and c-myc mRNA in abnormal chromosomal leukemic cells were 1.03 ± 0.48 and 1.15 ± 0.38 respectively, which were significantly higher than those in control group (P < 0.05). In the abnormal karyotype stromal cells, the mean expression level of c-myb mRNA and c-myc mRNA were 2.08 ± 0.82 and 1.46 ± 0.29 respectively (P < 0.05). (2) The expression level of c-myc and c-myb mRNA were closely associated with patients' platelet counts (P < 0.05). (3) The expression of c-myc mRNA linearly correlated with the expression of c-myb mRNA in different prognostic groups. (4) In acute leukemic cells and BMSC, c-myc expression positively correlated with c-myb expression. (5) The expression level of c-myc in leukemic cells correlated with the expression levels of c-myc and c-myb in BMSC, respectively. It is concluded that the reduction of c-myc or c-myb expression levels may be a therapeutic regimen for leukemia.

Prognostic value of MYB [6q23] deletion in sample of Egyptian B-cell patients

To assess the incidence and prognostic significance of MYB gene [6q23] deletion among a sample of Egyptian B-chronic lymphocytic leukemia [B-CLL] patients and to con elate it with other established prognostic factors This study was conducted on 63 newly diagnosed Egyptian B-CLL patients attending Am Shams University Hospitals. Fluorescence in situ hybridization [FISH] using locus specific identifier MYB [6q23] probe was applied on peripheral blood/bone marrow samples and was correlated with different established prognostic factors. Follow up was done through a period of 48 months to evaluate disease outcome. 6 patients had MYB deletion. All of them showed lymphocyte doubling time [LDT] more than 12 months and were CD38 positive. 83 3% of patients were good responders to therapy and none of these I atents died. B-CLL patients who were positive for MYB [6q23] deletion represent a cytogenetic entity associated with CD38 positivity and LDT>12 months They were considered as an intermediate risk group

Effect of protooncogene c-myb on progesterone-induced mouse germinal vesicle stage oocyte maturation in vitro / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of c-myb on progesterone-induced mouse germinal vesicle(GV) stage denuded oocyte (DO) maturation in vitro.</p><p><b>METHODS</b>We used mouse GV stage oocyte cultured with special concentration progesterone, or/and antisense c-myb ODN, or/and db-cAMP, or/and heparin for 24 h, and observed oocyte maturation and analysed the relationship among them.</p><p><b>RESULTS</b>We cultured DO in the medium 199 for 24 h, and found 10 micromol/L progesterone had more significant effect than 5 micromol/L progesterone (2 h GVBD% P < 0.05, 8 h PB 1% P < 0.05), but had not more significant effect than 20 micromol/L progesterone. We found that 16 micromol/L antisense c-myb ODN significantly inhibited progesterone (10 micromol/L)-induced mouse germinal vesicle stage oocyte maturation in vitro (2 h GVBD% P < 0.05, 8 h PBI% P < 0.01). 1 x 10(-4) micromol/L dbcAMP, 100 microg/ml heparin could single significantly inhibited progesterone-induced mouse GV stage oocyte maturation in vitro (2 h PBI% all P < 0.01, 8 h PBI% all P < 0.01), and could enhanced the inhibition of 16 micromol/L antisense c-myb ODN (2 h GVBD% all P < 0.01, 8h PBI% all P < 0.01).</p><p><b>CONCLUSION</b>Progesterone, protooncogene c-myb,cAMP and calcium all pay important role in regulating oocyte maturation and the mechanism of progesterone, cAMP and calcium in regulating oocyte maturation may be through the expression of protooncogene c-myb.</p>

Correlation analysis and identification of G421C in regulatory region of CYP4F2 gene with essential hypertension / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the correlation between G421C polymorphism in the regulatory region of CYP4F2 gene and essential hypertension and its molecular mechanism.</p><p><b>METHODS</b>Totally 196 hypertensive patients (hypertension group) and 219 normotensive subjects (control group) were genotyped by polymerase chain reaction-restriction fragment length polymorphism. The promoter activity with different alleles was evaluated by reporter assay. A Myb responsive element was identified using gel retardation assay.</p><p><b>RESULTS</b>Significant differences were found in distribution of genotype and allele frequency of G421C between hypertension group and control group (P < 0.05), and homozygous GG genotype was independently associated with hypertension after adjustment for age, gender, body mass index, and other risk factors (odds ratios 1.87, 95% CI 1.11-3.13, P < 0.05). 421G reporter construct showed decreased promoter activity compared with 421C reporter construct. 421G existed in Myb responsive element, whereas 421C damaged this motif.</p><p><b>CONCLUSION</b>G421C polymorphism in the regulatory region of CYP4F2 gene is correlated with essential hypertension. 421G allele inhibits transcription by binding affinity of Myb responsive element.</p>

In vivo distribution of c-myc antisense oligodeoxynucleotides local delivered by gelatin-coated platinum-iridium stents in rabbits and its effect on apoptosis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Post-stenting restenosis is a significant clinical problem, involving vascular smooth muscle cells (VSMCs) proliferation and apoptosis. It is reported that c-myc antisense oligodeoxynucleotides (ASODNs) local delivered by catheter can inhibit VSMCs proliferation. This study was designed to assess tissue distribution of c-myc ASODN local delivered using gelatin-coated platinum-iridium (Pt-Ir) stents, and its effect on apoptosis of VSMCs.</p><p><b>METHODS</b>Gelatin-coated Pt-Ir stents that had absorbed caroboxyfluorescein-5-succimidyl ester (FAM) labeled c-myc ASODNs (550 microg per stent) were implanted into the right carotid arteries of 6 rabbits. Tissue samples were obtained at 45 minutes, 2 hours, and 6 hours. Tissue distribution of c-myc ASODNs was assessed by fluorescence microscopy. In addition, 32 rabbits were randomly divided into two groups. Rabbits in the control group (n = 16) were implanted with gelatin-coated Pt-Ir stents, and those in the treatment group (n = 16) were implanted with gelatin-coated stents that had absorbed c-myc ASODNs. 7, 14, 30, or 90 days (n = 4, respectively, for each group) after the stenting procedure, the stented segments were harvested, and histopathological examinations were performed to calculate neointimal area and mean neointimal thickness. The expression of c-myc was assessed using in situ hybridization (ISH) and immunohistochemical methods. Apoptotic VSMCs were detected using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM).</p><p><b>RESULTS</b>According to fluorescence microscopic results, FAM-labeled c-myc ASODNs were concentrated in the target vessel media at the 45 minutes time point, and then dispersed to the adventitia. Morphometric analysis showed that neointimal area and mean neointimal thickness increased continuously up to 90 days after stent implantation, but that total neointimal area and mean neointimal thickness were less in the treatment group than in the control group at all time points (P < 0.0001). At day 7 and day 14 after stenting, there were no detectable apoptotic cells in either group. However, apoptotic cells were present in the neointima 30 and 90 days after stenting, and the number of apoptotic cells was less at 30 days than at 90 days. Meanwhile, c-myc ASODNs appeared to induce apoptosis in more cells in the treatment group than that in the control group. Typical apoptotic VSMCs were observable under TEM. The expression of c-myc was positive in the control group and negative or weakly positive in the c-myc ASODN treatment group, according to both ISH and immunohistochemical examination.</p><p><b>CONCLUSION</b>Gelatin-coated Pt-Ir stent mediated local delivery of c-myc ASODNs is feasible. The localization of c-myc ASODN is primarily in the target vessel walls. c-myc ASODNs can inhibit VSMCs proliferation and induce its apoptosis after local delivery in vivo.</p>

Growth Inhibition of Leukemic Cells by C-myb Antisense Oligos: Use of Simulational Target Site Search and Enhanced Delivery of Antisense Oligos by Cationic Liposomes / 대한혈액학회지

BACKGROUND: Aberrant expression of c-myb gene is often detected in transformed leukemic cells. Inhibition of c-myb expression by antisense oligos was shown to inhibit growth of normal as well as leukemic cells. C-myb antisense oligo for inhibition of tumor cell growth was, however, not decisive enough to be an effective anti-cancer agent. Thus, we set out to devise a systematic approach to find effective target sites for c-myb antisense oligos and to compare cellular uptake of antisense oligos complexed with different liposomes. METHODS: A computer simulation program for RNA secondary structures was employed to choose 8 potential target sites free of secondary structures along the entire c-myb mRNA sequence. Linear phosphorothioate-capped antisense oligos complementary to the selected target sites were synthesized and delivered into HL-60 and K562 cancer cell lines as liposomes complexes. RESULTS: Three of the 8 target sites were found to be relatively effective for reducing c-myb message. The three oliogs, MIJ-4, -17 and -18 were able to reduce c-myb message by more than 70% and suppressed tumor cell growth by about 70%. When three different cationic liposomes were used to facilitate the cellular uptake of antisense c-myb oligos, distinct liposome formulations were found to be comparably effective for reduction of c-myb message and inhibition of tumor cell growth. CONCLUSION: These results show that simulation of RNA secondary structure can be used to search effective target sites for antisense oligos and oligo uptake can be significantly enhanced by liposomes. However, cellular uptake of antisense oligos by liposomes needs further improvement.

Development of Covalently Closed c-myb Antisense Oligonucleotides for Growth Inhibition of Leukemic Cells / 대한암학회지

PURPOSE: Aberrant expression of the c-myb gene is often detected in transformed leukemic cells. Inhibition of c-myb expression by antisense oligos could be an effective way to abort rapid growth of leukemic cells. Developing stable antisense oligos combined with enhanced delivery into cells would be of great use in developing an effective anti-cancer molecular agent. MATERIALS AND METHODS: Selection of target sites was carried out by employing computer simulation of mRNA secondary structures. Multiple antisense oligo sequences were adjoined and AS-oligos were then covalently closed to evade exonuclease activities. C-myb antisense oligos with a novel structure were complexed with cationic liposomes and used to treat HL-60 leukemic cells. RESULTS: We developed covalently closed antisense oligos which harbor four adjoined antisense sequences. The c-myb antisense oligos were found to be exceptionally stable and effective in specifically ablating c-myb mRNA. The antisense oligos were able to inhibit growth of leukemic cell line (HL-60) by about 80%. Antisense effect was more pronounced when the cells were treated twice with the antisense oligos at lower concentrations. CONCLUSION: The novel covalently closed antisense oligo (CMAS-oligos) was found to be effective and exceptionally stable, Growth of HL-60 was significantly inhibited, showing a rational way to develop an effective molecular anti-cancer agent.