Identification of hookworm DAF-16/FOXO response elements and direct gene targets.
BACKGROUND
The infective stage of the parasitic nematode hookworm is developmentally arrested in the environment and needs to infect a specific host to complete its life cycle. The canine hookworm (Ancylostoma caninum) is an excellent model for investigating human hookworm infections. The transcription factor of A. caninum, Ac-DAF-16, which has a characteristic fork head or "winged helix" DNA binding domain (DBD), has been implicated in the resumption of hookworm development in the host. However, the precise roles of Ac-DAF-16 in hookworm parasitism and its downstream targets are unknown. In the present study, we combined molecular techniques and bioinformatics to identify a group of Ac-DAF-16 binding sites and target genes.


RESULTS
The DNA binding domain of Ac-DAF-16 was used to select genomic fragments by in vitro genomic selection. Twenty four bound genomic fragments were analyzed for the presence of the DAF-16 family binding element (DBE) and possible alternative Ac-DAF-16 bind motifs. The 22 genes linked to these genomic fragments were identified using bioinformatics tools and defined as candidate direct gene targets of Ac-DAF-16. Their developmental stage-specific expression patterns were examined. Also, a new putative DAF-16 binding element was identified.


CONCLUSIONS
Our results show that Ac-DAF-16 is involved in diverse biological processes throughout hookworm development. Further investigation of these target genes will provide insights into the molecular basis by which Ac-DAF-16 regulates its downstream gene network in hookworm infection.
Gao
Xin
X
Department of Microbiology and Tropical Medicine, The George Washington University Medical Center, Washington, District of Columbia, United States of America.
Wang
Zhengyuan
Z
Martin
John
J
Abubucker
Sahar
S
Zhang
Xu
X
Mitreva
Makedonka
M
Hawdon
John M
JM
D000595:Amino Acid Sequence; D000723:Ancylostomatoidea / Q000235:genetics* / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D005260:Female; D051858:Forkhead Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D020869:Gene Expression Profiling; D017238:Genes, Helminth / Q000235:genetics*; D023281:Genomics; D006801:Humans; D008024:Ligands; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D017434:Protein Structure, Tertiary; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D020218:Response Elements / Q000235:genetics*
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D008024:Ligands; D004247:DNA
Nat Genet. 2006 Feb;38(2):251-7
16380712
Proc Natl Acad Sci U S A. 1992 Sep 15;89(18):8754-8
1356269
Mol Cell. 1998 Dec;2(6):887-93
9885576
Science. 1990 Aug 3;249(4968):505-10
2200121
Nature. 1997 Oct 30;389(6654):994-9
9353126
Proc Natl Acad Sci U S A. 1984 Dec;81(23):7417-20
6209716
Int J Parasitol. 2010 Mar 15;40(4):405-15
19796644
Aging Cell. 2003 Apr;2(2):111-21
12882324
Proc Natl Acad Sci U S A. 2001 Nov 20;98(24):14000-5
11717458
Int J Parasitol. 2004 Jul;34(8):909-14
15217729
Nucleic Acids Res. 2009 Jan;37(Database issue):D571-8
18940860
Genes Dev. 2004 Oct 15;18(20):2529-44
15489294
Nature. 2003 Jul 17;424(6946):277-83
12845331
Adv Parasitol. 1963;1:109-77
14117619
Genetics. 1994 May;137(1):107-20
8056303
Structure. 2008 Sep 10;16(9):1407-16
18786403
Parasitol Today. 1993 Jan;9(1):23-6
15463660
Genes Dev. 1998 Aug 15;12(16):2488-98
9716402
Int J Parasitol. 2009 Mar;39(4):407-15
18930062
Int J Parasitol. 2003 Nov;33(13):1537-44
14572516
Physiol Rev. 2004 Jan;84(1):137-67
14715913
J Biosci Bioeng. 2006 May;101(5):440-4
16781475
Genetics. 2007 Mar;175(3):1407-18
17194779
Am J Physiol Endocrinol Metab. 2003 Nov;285(5):E1064-71
14534077
BMC Dev Biol. 2004 Sep 20;4:11
15380030
Lancet. 2006 May 6;367(9521):1521-32
16679166
Genetics. 1998 Feb;148(2):703-17
9504918
Protein Sci. 1995 Aug;4(8):1618-32
8520488
Int J Parasitol. 2006 Mar;36(3):347-52
16442538
Nucleic Acids Res. 2006 Jul 1;34(Web Server issue):W369-73
16845028
Parasit Vectors. 2009 Apr 24;2(1):21
19393088
Biochem J. 2000 Jul 15;349(Pt 2):629-34
10880363
Mol Biochem Parasitol. 2008 Feb;157(2):187-92
18082904
Cell. 1995 Oct 20;83(2):207-18
7585938
Nucleic Acids Res. 2004 Apr 23;32(7):e67
15107482
Science. 2003 Apr 25;300(5619):644-7
12690206
Nat Biotechnol. 2002 Aug;20(8):835-9
12101404
Nature. 1996 Aug 8;382(6591):536-9
8700226
Genome Res. 1997 Oct;7(10):986-95
9331369
Genome Res. 2004 Jun;14(6):1188-90
15173120
Science. 2009 Jun 26;324(5935):1720-3
19443739
Proc Natl Acad Sci U S A. 2000 Jan 4;97(1):460-5
10618440
Nature. 1993 Jul 29;364(6436):412-20
8332212
Curr Opin Cell Biol. 2009 Feb;21(1):109-18
19167202
Science. 1997 Aug 15;277(5328):942-6
9252323
Cell. 1989 May 19;57(4):645-58
2566386
Proc Natl Acad Sci U S A. 2009 Jul 21;106(29):12049-54
19584245
Nucleic Acids Res. 2008 Jan;36(Database issue):D107-13
18006570
Int J Parasitol. 2003 Jul 30;33(8):787-93
12865078
Dev Biol. 2005 Jun 1;282(1):231-45
15936343
Nucleic Acids Res. 2007;35(20):6984-94
17940099
BMC Genomics. 2005 Apr 26;6:58
15854223
Genes Dev. 1999 Jun 1;13(11):1438-52
10364160
Nucleic Acids Res. 2009 Mar;37(4):1323-34
19151087
BMC Genomics. 2010 May 14;11:307
20470405