title: Identification and characterization of a novel gene, c1orf109, encoding a CK2 substrate that is involved in cancer cell proliferation.
abstract: BACKGROUND
  In the present study we identified a novel gene, Homo Sapiens Chromosome 1 ORF109 (c1orf109, GenBank ID: NM_017850.1), which encodes a substrate of CK2. We analyzed the regulation mode of the gene, the expression pattern and subcellular localization of the predicted protein in the cell, and its role involving in cell proliferation and cell cycle control.
  
  
  METHODS
  Dual-luciferase reporter assay, chromatin immunoprecipitation and EMSA were used to analysis the basal transcriptional requirements of the predicted promoter regions. C1ORF109 expression was assessed by western blot analysis. The subcellular localization of C1ORF109 was detected by immunofluorescence and immune colloidal gold technique. Cell proliferation was evaluated using MTT assay and colony-forming assay.
  
  
  RESULTS
  We found that two cis-acting elements within the crucial region of the c1orf109 promoter, one TATA box and one CAAT box, are required for maximal transcription of the c1orf109 gene. The 5' flanking region of the c1orf109 gene could bind specific transcription factors and Sp1 may be one of them. Employing western blot analysis, we detected upregulated expression of c1orf109 in multiple cancer cell lines. The protein C1ORF109 was mainly located in the nucleus and cytoplasm. Moreover, we also found that C1ORF109 was a phosphoprotein in vivo and could be phosphorylated by the protein kinase CK2 in vitro. Exogenous expression of C1ORF109 in breast cancer Hs578T cells induced an increase in colony number and cell proliferation. A concomitant rise in levels of PCNA (proliferating cell nuclear antigen) and cyclinD1 expression was observed. Meanwhile, knockdown of c1orf109 by siRNA in breast cancer MDA-MB-231 cells confirmed the role of c1orf109 in proliferation.
  
  
  CONCLUSIONS
  Taken together, our findings suggest that C1ORF109 may be the downstream target of protein kinase CK2 and involved in the regulation of cancer cell proliferation.
authors.affiliation: Department of Life Science and Engineering, Harbin Institute of Technology, Harbin, 150001, People's Republic of China.
authors.forename: Shan-shan
authors.initials: SS
authors.lastname: Liu
authors.forename: Hong-xia
authors.initials: HX
authors.lastname: Zheng
authors.forename: Hua-dong
authors.initials: HD
authors.lastname: Jiang
authors.forename: Jie
authors.initials: J
authors.lastname: He
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.forename: You-peng
authors.initials: YP
authors.lastname: Qu
authors.forename: Lei
authors.initials: L
authors.lastname: Yue
authors.forename: Yao
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism; D047390:Casein Kinase II / Q000235:genetics / Q000378:metabolism*; D059447:Cell Cycle Checkpoints / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D006801:Humans; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D034741:RNA, Small Interfering; D013379:Substrate Specificity; D016385:TATA Box / Q000235:genetics; D015533:Transcriptional Activation
chemical_list: D047390:Casein Kinase II; D010750:Phosphoproteins; D034741:RNA, Small Interfering; C577075:AIRIM protein, human