A novel non-coding DNA family in Caenorhabditis elegans

Many repetitive elements, for example, SINEs, LINEs, LTR-retrotransposons and other SSRs are dispersed throughout eukaryotic genomes. To understand the biological function of these repetitive elements is of great current research interest. previous termInnext term this study, we report on the identification of previous terma novel non-coding DNA family,next term designated CE1 previous termfamily, innext term the nematode C. previous termelegansnext term genome. Some CE1 elements constituted previous termanext term large palindrome sequence. The CE1 elements were interspersed at 95 sites previous terminnext term the C. previous termelegansnext term genome. Most of the CE1 elements were associated with, or were within, protein-coding genes. The sequence of the CE1 elements indicated that some could form previous termanext term hairpin structure. One of the CE1 previous termfamily,next term CE1(bs258), is located previous terminnext term the first intron of previous terma novelnext term gene, C46H11.6 which encodes previous termanext term PDZ/DHR/GLGF domain protein. previous termInnext term gfp and lacZ reporter gene assays the CE1(bs258) element appeared to behave as an enhancer element for the expression of C46H11.6 but no effect on the expression of the opposite direction gene, pat-10 which encodes the body-wall muscle troponin C. The CE1(bs258) RNA transcript was detected by RT-PCR even when CE1(bs258) was located previous terminnext term an intron. We conclude that CE1 elements are involved previous terminnext term the expression of adjacent genes and are therefore selectively retained previous terminnext term the C. previous termelegansnext term genome. We discussed previous termanext term biological function of the CE1(bs258) having many transcription factor-binding sites.</p

Transcription Factors GATA/ELT-2 and Forkhead/HNF-3/PHA-4 Regulate the Tropomyosin Gene Expression in the Pharynx and Intestine of Caenorhabditis elegans

Gene regulation during development is an important biological activity that leads to synthesis of biomolecules at specific locations and specific times. The single tropomyosin gene of Caenorhabditis elegans, tmy-1/lev-11 produces four isoforms of protein: two from the external promoter and two from the internal promoter. We investigated the internal promoter of tropomyosin to identify sequences that regulate expression of tmy-1 in the pharynx and intestine. By promoter deletion of tmy-1 reporters as well as by database analyses, a 100 bp fragment was identified that contained binding sequences for a GATA factor, for a chicken CdxA homolog and for a forkhead factor. Both the forkhead and CdxA binding sequences contributed to pharyngeal and intestinal expression. In addition, the GATA site also influenced intestinal expression of tmy-1 reporter. We showed that ELT-2 and PHA-4 proteins interact directly with the GATA and forkhead binding sequences, respectively, in gel mobility shift assays. RNAi knockdown of elt-2 diminished tmy-1::gfp expression in the intestine. In contrast to RNAi knockdown of pha-4, expression of tmy-1::gfp in pha-4;smg-1 mutants was slightly weaker to that of the wild type. Ectopic expression of PHA-4 and ELT-2 by heat shock were sufficient to elicit widespread expression of tmy- 1::lacZ reporter in embryos. We found no indication of a synergistic relation between ELT-2 and PHA-4. Based on our data, PHA-4 and CdxA function as general transcription factors for pharyngeal and intestinal regulation of tmy-1. We present models by which ELT-2, PHA-4 and CdxA orchestrate expression from the internal promoter of tmy-1.</p

Contribution of histone N-terminal tails to the structure and stability of nucleosomes

AbstractHistones are the protein components of the nucleosome, which forms the basic architecture of eukaryotic chromatin. Histones H2A, H2B, H3, and H4 are composed of two common regions, the “histone fold” and the “histone tail”. Many efforts have been focused on the mechanisms by which the post-translational modifications of histone tails regulate the higher-order chromatin architecture. On the other hand, previous biochemical studies have suggested that histone tails also affect the structure and stability of the nucleosome core particle itself. However, the precise contributions of each histone tail are unclear. In the present study, we determined the crystal structures of four mutant nucleosomes, in which one of the four histones, H2A, H2B, H3, or H4, lacked the N-terminal tail. We found that the deletion of the H2B or H3 N-terminal tail affected histone–DNA interactions and substantially decreased nucleosome stability. These findings provide important information for understanding the complex roles of histone tails in regulating chromatin structure

Tissue-specific interactions of TNI isoforms with other TN subunits and tropomyosins in C. elegans: The role of the C- and N-terminal extensions

The aim of this study is to investigate the function of the C-terminal extension of three troponin I isoforms, that are unique to the body wall muscles of Caenorhabditis elegans and to understand the molecular interactions within the TN complex between troponin I with troponin C/T, and tropomyosin. We constructed several expression vectors to generate recombinant proteins of three body wall and one pharyngeal troponin I isoforms in Escherichia coli. Protein overlay assays and Western blot analyses were performed using antibodies. We demonstrated that pharyngeal TNI-4 interacted with only the pharyngeal isoforms of troponin C/T and tropomyosin. In contrast, the body wall TNI-2 bound both the body wall and pharyngeal isoforms of these components. Similar to other invertebrates, the N-terminus of troponin I contributes to interactions with troponin C. Full-length troponin I was essential for interactions with tropomyosin isoforms. Deletion of the C-terminal extension had no direct effect on the binding of the body wall troponin I to other muscle thin filament troponin C/T and tropomyosin isoforms

Long-term Survival with a Rare Advanced Primary Gastrointestinal Malignant Melanoma Treated with Laparoscopic Surgery/Immune Checkpoint Inhibitor

Targeted therapies for malignant melanoma have improved patients’ prognoses. A primary gastrointestinal malignant melanoma is very rare, with no standard treatment strategy. We treated a 78-year-old Japanese female with advanced primary gastrointestinal melanoma of the descending colon and gallbladder. We administered a multidisciplinary treatment: surgical resection of the descending colon and gallbladder tumors, resection of the metastatic lymph nodes behind the pancreas head, and immune checkpoint antibody-blockade therapy (nivolumab) for ~4 years. PET/CT demonstrated no recurrent lesion for > 3 years. Multidisciplinary therapies (e.g., surgery, chemotherapy, radiotherapy, target therapy, and immune checkpoint antibody-blockade therapy) can successfully treat primary gastrointestinal malignant melanoma

Fibroblast activation protein targeted near infrared photoimmunotherapy (NIR PIT) overcomes therapeutic resistance in human esophageal cancer

Cancer-associated fibroblasts (CAFs) have an important role in the tumor microenvironment. CAFs have the multifunctionality which strongly support cancer progression and the acquisition of therapeutic resistance by cancer cells. Near-infrared photoimmunotherapy (NIR-PIT) is a novel cancer treatment that uses a highly selective monoclonal antibody (mAb)-photosensitizer conjugate. We developed fibroblast activation protein (FAP)-targeted NIR-PIT, in which IR700 was conjugated to a FAP-specific antibody to target CAFs (CAFs-targeted NIR-PIT: CAFs-PIT). Thus, we hypothesized that the control of CAFs could overcome the resistance to conventional chemotherapy in esophageal cancer (EC). In this study, we evaluated whether EC cell acquisition of stronger malignant characteristics and refractoriness to chemoradiotherapy are mediated by CAFs. Next, we assessed whether the resistance could be rescued by eliminating CAF stimulation by CAFs-PIT in vitro and in vivo. Cancer cells acquired chemoradiotherapy resistance via CAF stimulation in vitro and 5-fluorouracil (FU) resistance in CAF-coinoculated tumor models in vivo. CAF stimulation promoted the migration/invasion of cancer cells and a stem-like phenotype in vitro, which were rescued by elimination of CAF stimulation. CAFs-PIT had a highly selective effect on CAFs in vitro. Finally, CAF elimination by CAFs-PIT in vivo demonstrated that the combination of 5-FU and NIR-PIT succeeded in producing 70.9% tumor reduction, while 5-FU alone achieved only 13.3% reduction, suggesting the recovery of 5-FU sensitivity in CAF-rich tumors. In conclusion, CAFs-PIT could overcome therapeutic resistance via CAF elimination. The combined use of novel targeted CAFs-PIT with conventional anticancer treatments can be expected to provide a more effective and sensible treatment strategy

A Novel Combination Cancer Therapy with Iron Chelator Targeting Cancer Stem Cells via Suppressing Stemness

Excess iron causes cancer and is thought to be related to carcinogenesis and cancer progression including stemness, but the details remain unclear. Here, we hypothesized that stemness in cancer is related to iron metabolism and that regulating iron metabolism in cancer stem cells (CSCs) may be a novel therapy. In this study, we used murine induced pluripotent stem cells that expressed specific stem cell genes such as Nanog, Oct3/4, Sox2, Klf4, and c-Myc, and two human cancer cell lines with similar stem cell gene expression. Deferasirox, an orally available iron chelator, suppressed expression of stemness markers and spherogenesis of cells with high stemness status in vitro. Combination therapy had a marked antitumor effect compared with deferasirox or cisplatin alone. Iron metabolism appears important for maintenance of stemness in CSCs. An iron chelator combined with chemotherapy may be a novel approach via suppressing stemness for CSC targeted therapy