title: Gene expression of flap endonuclease-1 during cell proliferation and differentiation.
abstract: It has been shown that flap endonuclease-1 (FEN-1), a structure-specific nuclease, acts on the removal of RNA primers during Okazaki fragment maturation in DNA synthesis. To study whether the gene expression of FEN-1 is inducible during cell proliferation, we analyzed the FEN-1 mRNA levels in actively growing cells and non-growing cells. The gene expression of FEN-1 was higher in mitotic cells than in resting cells, and was markedly decreased, especially, when terminal differentiation was induced in promyelocytic leukemia cells (HL-60 cells). The decline correlated substantially with the ceasing of DNA synthesis. In the examination of tissue-specific gene expression, the human testis, spleen, thymus and mucosal lining of colon tissues expressed this gene actively, whereas the prostate, ovary, small intestine and peripheral blood leukocyte hardly expressed it. In addition, FEN-1 was co-localized with the proliferating cell nuclear antigen (PCNA) in young rat kidney according to immunohistochemistry. These findings suggest that FEN-1 gene expression is inducible during cell proliferation for DNA synthesis, and is down-regulated during cell differentiation.
authors.affiliation: Department of Natural Sciences, Chemistry Section, College of Medicine, The Catholic University of Korea, 505 Banpo-Dong, Socho-Gu, Seoul, South Korea. ikim@cmc.cuk.ac.kr
authors.forename: I S
authors.initials: IS
authors.lastname: Kim
authors.forename: M Y
authors.initials: MY
authors.lastname: Lee
authors.forename: I H
authors.initials: IH
authors.lastname: Lee
authors.forename: S L
authors.initials: SL
authors.lastname: Shin
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D004247:DNA / Q000032:analysis / Q000096:biosynthesis; D004261:DNA Replication; D004706:Endodeoxyribonucleases / Q000096:biosynthesis / Q000235:genetics*; D045585:Flap Endonucleases; D015971:Gene Expression Regulation, Enzymologic; D006098:Granulocytes / Q000166:cytology; D018922:HL-60 Cells; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology; D008297:Male; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000378:metabolism; D013737:Testis / Q000378:metabolism
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D004247:DNA; D004706:Endodeoxyribonucleases; D045585:Flap Endonucleases; C468317:FEN1 protein, human