title: Identification of potential target genes for RFX4_v3, a transcription factor critical for brain development.
abstract: Regulatory factor X4 variant transcript 3 (Rfx4_v3) gene disruption in mice demonstrated that interruption of a single allele (heterozygous, +/-) prevented formation of the subcommissural organ, resulting in congenital hydrocephalus, while interruption of two alleles (homozygous, -/-) caused fatal failure of dorsal midline brain structure formation. To identify potential target genes for RFX4_v3, we used microarray analysis to identify differentially expressed genes in Rfx4_v3-deficient mouse brains at embryonic day 10.5, before gross structural changes were apparent. Of 109 differentially expressed transcripts, 24 were chosen for validation and 22 were confirmed by real-time PCR. Many validated genes encoded critical proteins involved in brain morphogenesis, such as the signaling components in the Wnt, bone morphogenetic protein (BMP) and retinoic acid (RA) pathways. Cx3cl1, a CX3C-type chemokine gene that is highly expressed in brain, was down-regulated in the Rfx4_v3-null mice. Both human and mouse Cx3cl1 proximal promoters contained highly conserved X-boxes, known cis-acting elements for RFX protein binding. Using the Cx3cl1 promoter as an example of a target gene, we demonstrated direct binding of RFX4_v3 to the Cx3cl1 promoter, and trans-acting activity of RFX4_v3 protein to stimulate gene expression. These data suggest that RFX4_v3 may act upstream of critical signaling pathways in the process of brain development.
authors.affiliation: Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health Research Triangle Park, North Carolina 27709, USA.
authors.forename: Donghui
authors.initials: D
authors.lastname: Zhang
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Stumpo
authors.forename: Joan P
authors.initials: JP
authors.lastname: Graves
authors.forename: Laura M
authors.initials: LM
authors.lastname: DeGraff
authors.forename: Sherry F
authors.initials: SF
authors.lastname: Grissom
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Collins
authors.forename: Leping
authors.initials: L
authors.lastname: Li
authors.forename: Darryl C
authors.initials: DC
authors.lastname: Zeldin
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Blackshear
mesh_terms: D000818:Animals; D001483:Base Sequence / Q000235:genetics; D001921:Brain / Q000254:growth & development* / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018390:Gene Targeting / Q000379:methods*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D000071701:Regulatory Factor X Transcription Factors; C479564:Rfx4 protein, mouse; D014157:Transcription Factors