ABSTRACT
The SP/KLF transcription factor family contains over 25 members sharing a DNA-binding domain composed of three zinc fingers of the C(2)H(2) type. We previously identified the sixth member of the SP subfamily (Sp6). The 5' end of the Sp6 transcript was not cloned and was predicted bioinformatically. A mouse molar tooth cDNA was then isolated differing from the Sp6 sequence by its 5' end, and was named epiprofin. Sp6 and epiprofin are currently used as synonyms. Here, we show that the Sp6 transcript possesses a first exon distinct from the epiprofin one: the Sp6 gene thus uses two promoters, generating two transcript variants which differ in their first exon. Furthermore, we identified an Sp6 opposite strand transcript (Sp6os) and examined, by quantitative RT-PCR experiments, the presence and the abundance of these two transcripts in mouse tissues. We also mapped the mouse locus by FISH to chromosome 11D.
Subject(s)
Kruppel-Like Transcription Factors/genetics , Promoter Regions, Genetic/genetics , RNA, Antisense/genetics , Animals , Base Sequence , Gene Expression , Gene Expression Profiling , In Situ Hybridization, Fluorescence , Male , Mice , Mice, Inbred Strains , Molecular Sequence Data , Physical Chromosome Mapping , RNA, Messenger/genetics , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Transcription Factors/genetics , Transcription Initiation SiteABSTRACT
Ammonium excretion into urine is a major process essential to the regulation of acid-base homeostasis. We have shown that Rh-type proteins, including renal RhCG, belong to the Mep/Amt family of ammonium transporters and promote bi-directional ammonium transport upon heterologous expression in yeast. To study the physiological role of RhCG and to test a potential function in ammonium excretion, we have generated mice bearing an invalidation of the corresponding gene.
Subject(s)
Cation Transport Proteins/physiology , Membrane Glycoproteins/physiology , Quaternary Ammonium Compounds/metabolism , Acidosis/metabolism , Animals , Blood Proteins/genetics , Blood Proteins/metabolism , Cation Transport Proteins/biosynthesis , Cation Transport Proteins/deficiency , Cation Transport Proteins/genetics , Cation Transport Proteins/metabolism , Glycoproteins/metabolism , Humans , Ion Transport , Kidney/metabolism , Liver/metabolism , Membrane Glycoproteins/biosynthesis , Membrane Glycoproteins/deficiency , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Membrane Transport Proteins/metabolism , Mice , Mice, Knockout , Multigene Family , Rats , Recombinant Fusion Proteins/metabolism , Saccharomyces cerevisiae/metabolismABSTRACT
Using the sequence of the SP1 zinc-finger DNA-binding domain as a probe to screen a mouse EST database, we identified two novel members of the SP/XKLF transcription factor family, KLF13 and KLF14. The mouse Klf13 cDNA (1310 bp in length) contains a single open reading frame of 288 amino acids with a DNA-binding domain closely related to that of the human RFLAT-1 protein and a putative transactivator N-terminal domain rich in proline and alanine residues. The mouse Klf13 gene seems to be the homologue of the human RFLAT1 gene. The mouse Klf14 sequence is homologous to a human genomic sequence from chromosome 17 that is believed to code for a protein with three zinc fingers at the end of its C-terminal domain. Using reverse transcription-polymerase chain reaction, we showed ubiquitous expression of Klf13 and Klf14 in adult mice. A third member of this family was also identified in a human EST database; this sequence was found to be identical to KLF11 (TIEG2), recently identified by Cook et al. (1998, J. Biol. Chem. 273: 25929-25936). The corresponding mouse cDNA was isolated and sequenced. The three genes were localized in the human and the rat: chromosomes 15 (human KLF13), 17q21.3-q22 (human KLF14; HGMW-approved symbol SP6), and 2p25 (human KLF11) and chromosomes 1q31-q32 (rat Klf13), 10q31-q32.1 (rat Klf14) (SP6), and 6q16-q21 (rat Klf11).
Subject(s)
Multigene Family , Trans-Activators/genetics , Transcription Factors/genetics , Zinc Fingers , Amino Acid Sequence , Animals , Apoptosis Regulatory Proteins , Base Sequence , Cell Cycle Proteins/genetics , Chromosome Mapping , Chromosomes, Human, Pair 15 , Expressed Sequence Tags , Humans , Kruppel-Like Transcription Factors , Mice , Molecular Sequence Data , Rats , Repressor Proteins/genetics , Sequence Homology, Amino Acid , Sp Transcription Factors , Trans-Activators/classification , Transcription Factors/classificationABSTRACT
In this study we have characterized a positive regulatory region located in the first intron of the alpha-fetoprotein (AFP) gene. We show that the enhancer activity of the region depends on a 44 bp sequence centered on a CACCC motif. The sequence is the target of the two zinc fingers transcription factors BKLF and YY1. The introduction of a mutation destroying the CACCC box impairs the binding of BKLF but improves that of YY1. Moreover, the mutated sequence behaves as a negative control element, suggesting that BKLF behaves as a positive factor and that YY1 is a negative one. We also demonstrate the existence of a novel, tissue-specific AFP mRNA isoform present in the yolk sac and fetal liver which initiates from an alternative promoter located approximately 100 bp downstream of the enhancer element. The transcriptional start site controlled by this new promoter (called P2), was mapped to 66 bp downstream of a TATA box. A putative AUG translation site in-frame with exon 2 of the classical gene was found 295 bp downstream of the transcription start site. Like the traditional AFP promoter (P1), the P2 promoter is active in the yolk sac and fetal liver. Embryonic stem cells with an AFP knock-in gene containing either the P2 promoter or deleted for it were isolated and comparative analysis of embryonic bodies derived from these cells suggests that the P2 promoter contributes to early expression of the AFP gene.
Subject(s)
Enhancer Elements, Genetic/genetics , Introns/genetics , Promoter Regions, Genetic/genetics , alpha-Fetoproteins/genetics , Animals , Base Sequence , Binding Sites , Codon, Initiator/genetics , DNA/genetics , DNA/metabolism , DNA-Binding Proteins/metabolism , Erythroid-Specific DNA-Binding Factors , Exons/genetics , Gene Expression Regulation, Developmental , Genes, Reporter/genetics , Humans , Kruppel-Like Transcription Factors , Liver/embryology , Liver/metabolism , Mice , Molecular Sequence Data , Mutation/genetics , Organ Specificity , RNA, Messenger/analysis , RNA, Messenger/genetics , Repressor Proteins/metabolism , Response Elements/genetics , Stem Cells/metabolism , TATA Box/genetics , Transcription Factors/metabolism , Transcriptional Activation/genetics , Transfection , Tumor Cells, Cultured , YY1 Transcription Factor , Yolk Sac/metabolism , Zinc FingersABSTRACT
In order to improve the rat gene map and comparative mapping with the human and the mouse, we determined the chromosome localization of 54 rat genes. Most genes encode transcription factors or other regulatory proteins of cancer relevance. The human homologs of four genes were also assigned to their respective chromosome. These data generated anchor points between the recently established radiation hybrid maps and the genetic and cytogenetic maps. They improve comparative mapping between the rat, the mouse, and the human gene maps, and in particular they disclose four new synteny groups conserved in the rat and the human. These new localizations should also be useful for the identification of genes involved in the control of quantitative traits such as cancer susceptibility or diabetes.
