title: Silk gland factor-2, involved in fibroin gene transcription, consists of LIM homeodomain, LIM-interacting, and single-stranded DNA-binding proteins.
abstract: SGF-2 binds to promoter elements governing posterior silk gland-specific expression of the fibroin gene in Bombyx mori. We purified SGF-2 and showed that SGF-2 contains at least four gene products: the silkworm orthologues of LIM homeodomain protein Awh, LIM domain-binding protein (Ldb), a sequence-specific single-stranded DNA-binding protein (Lcaf), and the silk protein P25/fibrohexamerin (fhx). Using co-expression of these factors in Sf9 cells, Awh, Ldb, and Lcaf proteins were co-purified as a ternary complex that bound to the enhancer sequence in vitro. Lcaf interacts with Ldb as well as Awh through the conserved regions to mediate transcriptional activation in yeast. Misexpression of Awh in transgenic silkworms induces ectopic expression of the fibroin gene in the middle silk glands, where Ldb and Lcaf are expressed. Taken together, this study demonstrates that SGF-2 is a multisubunit activator complex containing Awh. Moreover, our results suggest that the Ldb·Lcaf protein complex serves as a scaffold to facilitate communication between transcriptional control elements.
authors.affiliation: From the National Institute for Basic Biology, 38 Nishigonaka, Myodaiji-cho, Okazaki 444-8585.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ohno
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Sawada
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Takiya
authors.forename: Mai
authors.initials: M
authors.lastname: Kimoto
authors.forename: Akiko
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Takuya
authors.initials: T
authors.lastname: Tsubota
authors.forename: Keiro
authors.initials: K
authors.lastname: Uchino
authors.forename: Chi-chung
authors.initials: CC
authors.lastname: Hui
authors.forename: Hideki
authors.initials: H
authors.lastname: Sezutsu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Handa
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Suzuki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005349:Fibroins / Q000096:biosynthesis* / Q000235:genetics; D060850:LIM-Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D020218:Response Elements / Q000502:physiology; D061987:Sf9 Cells; D018411:Spodoptera; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D060850:LIM-Homeodomain Proteins; D015534:Trans-Activators; D005349:Fibroins
keywords: Fibroin Gene; Gene transcription; Homeobox; Homeodomain; Silk gland factor-2 (SGF-2); Silkworm; Tissue-specific transcription factors; Transcription enhancers
references.citation: J Biol Chem. 2000 Dec 22;275(51):40517-28
references.pmid: 10986287
references.citation: EMBO J. 1990 Feb;9(2):489-96
references.pmid: 2303038
references.citation: Proc Natl Acad Sci U S A. 2002 Oct 29;99(22):14320-5
references.pmid: 12381786
references.citation: Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11693-8
references.pmid: 8876198
references.citation: Trends Genet. 2006 Jan;22(1):38-45
references.pmid: 16309780
references.citation: Cell. 2012 Jun 8;149(6):1233-44
references.pmid: 22682246
references.citation: Biochem J. 1998 Apr 15;331 ( Pt 2):447-52
references.pmid: 9531483
references.citation: Insect Biochem Mol Biol. 2007 Jul;37(7):713-25
references.pmid: 17550827
references.citation: J Biol Chem. 1982 Dec 25;257(24):15192-9
references.pmid: 6294094
references.citation: J Biol Chem. 1995 Apr 21;270(16):9340-6
references.pmid: 7721856
references.citation: J Biol Chem. 1998 Feb 20;273(8):4712-7
references.pmid: 9468533
references.citation: Oncogene. 1994 Jul;9(7):1839-46
references.pmid: 8208529
references.citation: Development. 2003 May;130(9):1915-25
references.pmid: 12642495
references.citation: Proc Natl Acad Sci U S A. 1986 Dec;83(24):9522-6
references.pmid: 3467322
references.citation: Development. 2000 May;127(9):1823-31
references.pmid: 10751171
references.citation: Proc Natl Acad Sci U S A. 2007 May 22;104(21):8941-6
references.pmid: 17496138
references.citation: Curr Opin Genet Dev. 1999 Oct;9(5):505-14
references.pmid: 10508687
references.citation: Proc Natl Acad Sci U S A. 1983 Dec;80(24):7442-6
references.pmid: 6324171
references.citation: Nature. 1996 Nov 21;384(6606):270-2
references.pmid: 8918878
references.citation: Insect Biochem Mol Biol. 1999 Mar;29(3):269-76
references.pmid: 10319440
references.citation: Nucleic Acids Res. 2005 Feb 01;33(2):786-95
references.pmid: 15687387
references.citation: Genetics. 1996 Nov;144(3):1143-54
references.pmid: 8913756
references.citation: Biol Cell. 1995;84(1-2):43-52
references.pmid: 8574197
references.citation: Dev Biol. 1987 Dec;124(2):431-40
references.pmid: 3678608
references.citation: Dev Biol. 1983 Jun;97(2):398-407
references.pmid: 6852371
references.citation: Dev Biol. 1997 Oct 1;190(1):129-41
references.pmid: 9331336
references.citation: Genes Dev. 1997 Oct 15;11(20):2729-40
references.pmid: 9334334
references.citation: J Mol Biol. 1974 Sep 15;88(2):393-407
references.pmid: 4453002
references.citation: Cell. 1993 Jul 16;74(1):205-14
references.pmid: 8334704
references.citation: EMBO J. 2000 Jun 1;19(11):2602-14
references.pmid: 10835358
references.citation: Genes Dev. 2007 Apr 15;21(8):942-55
references.pmid: 17437998
references.citation: Genes Dev. 1997 Jun 1;11(11):1370-80
references.pmid: 9192866
references.citation: Insect Biochem Mol Biol. 2010 Apr;40(4):339-44
references.pmid: 20197092
references.citation: Trends Genet. 2000 Feb;16(2):75-83
references.pmid: 10652534
references.citation: Biochim Biophys Acta. 2002 Sep 23;1599(1-2):152-5
references.pmid: 12479417
references.citation: Biochem J. 1997 Feb 1;321 ( Pt 3):645-53
references.pmid: 9032449
references.citation: Cell. 1981 Nov;27(1 Pt 2):175-82
references.pmid: 7326750
references.citation: EMBO J. 2004 Jul 21;23(14):2841-52
references.pmid: 15215894
references.citation: Nucleic Acids Res. 1986 Aug 11;14(15):6341-2
references.pmid: 3748814
references.citation: Oncogene. 2010 May 27;29(21):3044-53
references.pmid: 20348955
references.citation: J Mol Biol. 1990 Jun 20;213(4):651-70
references.pmid: 2359119
references.citation: J Biol Chem. 1988 Apr 25;263(12):5979-86
references.pmid: 3128549