RESUMO
We report the screening of thirty-one YACs with a number of markers using polymerase chain reaction (PCR) to construct a physical map of part of human chromosome 17q21.3-q22. A contig of YACs covering about 4 Mb was constructed around the TCF11 gene at 68 cM from the most telomeric marker on the p arm, localizing TCF11 telomeric to genetic marker D17S1827. Both human and mouse P1-derived artificial chromosomes (PACs) containing TCF11 were isolated and characterized. The human heterochromatin protein 1 gene, HP1Hsbeta, and its homologue in mouse, MoMOD1, were identified centromeric to TCF11.
Assuntos
Cromossomos Humanos Par 17 , Zíper de Leucina , Mapeamento Físico do Cromossomo , Fatores de Transcrição/genética , Animais , Cromossomos Artificiais de Levedura , Mapeamento de Sequências Contíguas , Éxons , Humanos , Camundongos , Dados de Sequência Molecular , Fator 1 Relacionado a NF-E2 , Mapeamento por Restrição , Alinhamento de Sequência , TelômeroRESUMO
The human TCF11 gene encodes a ubiquitously expressed bZIP transcription factor of the cap n' collar (CNC) domain family. It has a high sequence similarity to the erythroid-specific bZIP factor p45 NF-E2 in the CNC domain, which is involved in DNA binding. LCR-F1, a TCF11 isoform, is a more potent transcriptional activator than p45 NF-E2 in erythroid cells. We show here that the TCF11 protein interacts to form heterodimers with small Maf proteins, previously shown to dimerize with p45 NF-E2, ECH and Fos. Such heterodimerization significantly alters the DNA binding characteristics of TCF11. While TCF11 alone binds in vitro to the tandem NF-E2 site derived from 5' DNase hypersensitive site 2 in the beta-globin locus control region and to the single NF-E2 site in the porphobilinogen deaminase gene promoter, stronger binding is detected in the presence of small Maf proteins. Using antibodies, TCF11 isoforms bound to the single NF-E2 site were detected in K562 erythroid cell nuclear extracts. These findings place TCF11 as a good candidate for the proposed widely expressed factor(s) known to interact with small Maf proteins and bind NF-E2 sites in a sequence-specific manner resembling NF-E2.
Assuntos
Proteínas Aviárias , Proteínas de Ligação a DNA/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Fatores de Transcrição/metabolismo , Sítios de Ligação , DNA/metabolismo , Fatores de Ligação de DNA Eritroide Específicos , Humanos , Hidroximetilbilano Sintase/genética , Imunoensaio , Zíper de Leucina , Fator de Transcrição MafB , Fator de Transcrição MafF , Fator de Transcrição NF-E2 , Subunidade p45 do Fator de Transcrição NF-E2 , Fator 1 Relacionado a NF-E2 , Proteínas Nucleares/metabolismo , Fator 1 Nuclear Respiratório , Fatores Nucleares Respiratórios , Proteínas Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-maf , Transativadores/metabolismoRESUMO
We recently cloned human cDNA representing several mRNA isoforms of human TCF11, a transcription factor of the basic-region, leucine-zipper (bZIP) family located on chromosome 17q22 as well as a genomic clone of this gene. We have now determined the complete genomic organization of the TCF11 gene, which consists of 9 exons distributed over 15 kb of genomic DNA. Pulsed-field gel electrophoresis was used to construct a physical map around TCF11, to characterize a 450-kb YAC clone that contains the gene, and to link TCF11 physically to BTR, a marker on chromosome 17.
