(M.-C.C., T.P., P.G.)Many G2/M phase-specific genes in plants contain mitosis-specific activator (MSA) elements, which act as G2/M phasespecific enhancers and bind with R1R2R3-Myb transcription factors. Here, we examined the genome-wide effects of NtmybA2 overexpression, one of the R1R2R3-Myb transcription factors in tobacco (Nicotiana tabacum). We used a custom-made 16-K cDNA microarray for comparative transcriptome analysis of transgenic tobacco BY-2 cell lines that overexpress NtmybA2 or its truncated hyperactive form. The microarray was also used to determine the transcript profile during the cell cycle in synchronized cultures of BY-2 cells. Combined microarray data from transgenic lines and synchronized cells revealed that overexpression of the truncated hyperactive form of NtmybA2, but not its full-length form, preferentially up-regulated many G2/M phase-specific genes in BY-2 cells. We determined promoter sequences of several such up-regulated genes and showed that all contain MSA-like motifs in the proximal regions of their promoters. One of the up-regulated genes, NtE2C, encoding for cyclin-specific ubiquitin carrier proteins, contained a single functional MSA-like motif, which specifically controlled the expression of a reporter gene in the G2/M phase in BY-2 cells. Furthermore, a genomic footprint experiment showed that the MSA element in the NtE2C promoter interacted with nuclear proteins in vivo. Therefore, we propose that the transcription of many G2/M phase-specific genes in tobacco is positively regulated by NtmybA2, in most cases through direct binding to the MSA elements.
POAG patients had a weaker vasoreactive response to hyperoxia than controls, and this impaired response was associated with lower basal ONH BF and higher SBP. These findings suggest that pre-existing vasoconstriction in the ONH of eyes with glaucoma might reduce the capacity of the vasoconstrictive response to hyperoxia. Alternatively, the pathways that mediate hyperoxia-induced vasoconstriction could be altered in POAG.
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A 15-year-old old Japanese male with a 2-month history of swelling of his left subauricular area was admitted to our department. A thumb-sized, hard mass with mild tenderness was palpated on the left parotid gland. Ultrasonography revealed a well-circumscribed, hypoechoic mass exhibiting heterogeneity in the left parotid gland measuring 1.7 × 1.5 × 1.3 cm. Computed tomography scan revealed a well-circumscribed, solid mass exhibiting slight peripheral enhancement in the left parotid gland. Magnetic resonance imaging revealed a hypointense mass in the left parotid gland on both T1-and T2-weighted images. Clinicoradiologic findings suggested a benign or low-grade malignant parotid tumor. The patient underwent left superficial parotidectomy with adequate safety margins. The facial nerve was identified and preserved. Neither facial paralysis nor tumor recurrence was observed as of 1 year postoperatively. Histologically, the nodule consisted of a vaguely nodular arrangement of variably sized ducts and acini in a hyalinized fibrous background with focal myxoid changes. The ductal/ acinar component exhibited a bilayered arrangement of cuboidal luminal and flattened abluminal cells exhibiting a variety of epithelial proliferative patterns, including micropapillary and cribriform. Areas of oncocyte-like changes with intracellular coarse eosinophilic granules, apocrine-like feature, foamy/vacuolated changes, and clear cells were noted in the proliferating epithelium. Immunohistologically, the luminal cells were positive for gross cystic disease fluid protein-15. The Ki-67 labeling index was 2-3%. The histologic features and immunohistologic profile were consistent with sclerosing polycystic adenosis. Targeted next-generation sequencing of 160 cancer-related genes using the surgical specimen revealed no mutations, including known significant mutations in PTEN, PIK3CA, or PIK3R1.
Background and Aim: Chronic hepatitis C virus (HCV) infection, long-term alcohol use, cigarette smoking, and obesity are the major risk factors for hepatocellular carcinoma (HCC) in the United States, but the disease risk varies substantially among individuals with these factors, suggesting host susceptibility to and gene-environment interactions in HCC. To address genetic susceptibility to HCC, we conducted a genome-wide association study (GWAS). Methods: Two case-control studies on HCC were conducted in the United States. DNA samples were genotyped using the Illumian microarray chip with over 710 000 single nucleotide polymorphisms (SNPs). We compared these SNPs between 705 HCC cases and 1455 population controls for their associations with HCC and verified our findings in additional studies. Results: In this GWAS, we found that two SNPs were associated with HCC at P < 5E-8 and six SNPs at P < 5E-6 after adjusting for age, sex, and the top three principal components (PCs). Five of the SNPs in chromosome 22q13.31, three in PNPLA3 (rs2281135, rs2896019, and rs4823173) and two in SAMM50 (rs3761472, rs3827385), were replicated in a small US case-control study and a cohort study in Singapore. The associations remained significant after adjusting for body mass index and HCV infection. Meta-analysis of multiple datasets indicated that these SNPs were significantly associated with HCC. Conclusions: SNPs in PNPLA3 and SAMM50 are known risk loci for nonalcoholic fatty liver disease (NAFLD) and are suspected to be associated with HCC. Our GWAS demonstrated the associations of these SNPs with HCC in a US population. Biological mechanisms underlying the relationship remain to be elucidated.
The tumor suppressor gene p53 encodes a transcriptional activator that has two transactivation domains (TAD) located in its amino terminus. These two TAD can transactivate genes independently, and at least one TAD is required for p53 transactivation function. The 1st TAD (a.a. 1-40) is essential for the induction of numerous classical p53 target genes, while the second TAD (a.a. 41-61) suffices for tumor suppression, although its precise molecular function remains unclear. In this study, we comprehensively identified the sites to which p53 lacking the 1st TAD (Δ1stTAD-p53) binds, as well as its potential target genes. We found that the binding sequences for Δ1stTAD-p53 are divergent and include not only the canonical p53 consensus binding sequences but also sequences similar to those recognized by a number of other known transcription factors. We identified and analyzed the functions of three Δ1stTAD-p53 target genes, PTP4A1, PLK2 and RPS27L. All three genes were induced by both full-length p53 and Δ1stTAD-p53, and were dependent on the transactivation activity of the 2nd TAD.We also found that two of these, PTP4A1 and PLK2, are endoplasmic reticulum (ER) stress-inducible genes. We found that upon ER stress, PTP4A1 suppresses apoptosis while PLK2 induces apoptosis. These results reveal a novel Δ1stTAD-p53 downstream pathway that is dependent on the transcription activation activity of the 2nd TAD. K E Y W O R D S endoplasmic reticulum stress, p53, p53 isoform, Suzuki, transactivation domain, tumor suppressor S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section. How to cite this article: Suzuki S, Tsutsumi S, Chen Y, et al. Identification and characterization of the binding sequences and target genes of p53 lacking the 1st transactivation domain. Cancer Sci. 2020;111:451-466. https ://doi.
An East Asian-specific variant on aldehyde dehydrogenase 2 (ALDH2 rs671, G>A) is the major genetic determinant of alcohol consumption. We performed an rs671 genotype-stratified genome-wide association study meta-analysis in up to 40,679 individuals from Japanese populations to uncover additional loci associated with alcohol consumption in an rs671-dependent manner. No loci satisfied the genome-wide significance threshold in wild-type homozygotes (GG), but six loci (ADH1B, ALDH1B1, ALDH1A1, ALDH2, GOT2, and MYOM1- MYL12A) did so in heterozygotes (GA). Of these, three loci (ALDH2, GOT2, and MYOM1- MYL12A) were novel, and two (ADH1B and ALDH1B1) showed genome-wide significant interaction with rs671. Our results identify a new genetic architecture associated with alcohol consumption, and shed additional light on the genetic characteristics of alcohol consumption among East Asians.
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