RESUMO
BACKGROUND: The level of circulating interleukin-6 receptor in human blood varies depending on the genetic and/or physiological causes, and has been implicated in the development of chronic inflammatory diseases. METHOD: The cis-regulatory effects of genetic variations on the transcription of interleukin-6 receptor gene, IL6R,were studied by assessing allelic transcriptions in the immortalized lymphocytes derived from unrelated and familial samples. RESULTS: The assays for allelic transcription in the cells from unrelated subjects demonstrated an extensive and variable range of allelic transcriptional imbalances, suggesting an operation of multiple cis-regulations with varying degrees on the locus. Analysis of the familial samples illustrated the Mendelian inheritance of allelic transcriptions,enabling us to assign each haplotype allele into one of the 3 transcriptional strengths. A comparison of the allele structures based on the transcriptional attributes highlighted 2 SNP variations, rs952146 and rs4845617, as being associated with higher allelic transcription. Consistently, lymphocytes that were homozygous for the 2SNPs exhibited differences in their transcript levels depending on the haplotypes. CONCLUSION: Inheritance assessment of allelic transcription of IL6R identified 2 SNPs that are associated with transcriptional variation in cis. GENERAL SIGNIFICANCE: Our results not only demonstrate genetic variations that are associated with IL6R transcription in cis but also demonstrate an effective genetic approach for isolating cis-regulatory variations.
Assuntos
Desequilíbrio Alélico , Regulação da Expressão Gênica , Padrões de Herança , Polimorfismo de Nucleotídeo Único/genética , Regiões Promotoras Genéticas/genética , Receptores de Interleucina-6/genética , Sequências Reguladoras de Ácido Nucleico/genética , Transcrição Gênica , Alelos , DNA/genética , Família , Feminino , Haplótipos/genética , Humanos , Masculino , Linhagem , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Calmodulin (CaM), a key Ca2+ sensor, regulates diverse cellular processes by modulating the activity of a variety of enzymes and proteins. However, little is known about the biological function of CaM in plant development. In this study, an ASYMMETRIC LEAVES1 (AS1) transcription factor was isolated as a CaM-binding protein. AS1 contains two putative CaM-binding domains (CaMBDs) at the N-terminus. Using domain mapping analysis, both predicted domains were identified as authentic Ca2+ -dependent CaMBDs. We identified three hydrophobic amino acid residues for CaM binding, Trp49 in CaMBDI, and Trp81 and Phe103 in CaMBDII. The interactions of AS1 with CaM were verified in yeast and plant cells. Based on electrophoretic mobility shift assays, CaM inhibited the DNA-binding activity of the AS1/AS2 complex to two cis-regulatory motifs in the KNAT1 promoter. Furthermore, CaM relieved the suppression of KNAT1 transcription by AS1 not only in transient expression assays of protoplasts but also by the overexpression of a CaM-binding negative form of AS1 in as1 mutant plant. Our study suggests that CaM, a calcium sensor, can be involved in the transcriptional control of meristem cell-specific genes by the inhibition of AS1 under the condition of higher levels of Ca2+ in plants.
Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/genética , Proteínas de Ligação a Calmodulina/fisiologia , Calmodulina/fisiologia , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/fisiologia , Agrobacterium tumefaciens/genética , Sequência de Aminoácidos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Sítios de Ligação , Calmodulina/metabolismo , Proteínas de Ligação a Calmodulina/metabolismo , Mapeamento Cromossômico , Escherichia coli/genética , Biblioteca Gênica , Proteínas de Homeodomínio/genética , Meristema/crescimento & desenvolvimento , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas , Nicotiana/genética , Fatores de Transcrição/química , Fatores de Transcrição/genéticaRESUMO
Plant cells often use cell surface receptors to sense environmental changes and then transduce external signals via activated signaling pathways to trigger adaptive responses. In Arabidopsis, the receptor-like protein kinase (RLK) gene family contains more than 600 members, and some of these are induced by pathogen infection, suggesting a possible role in plant defense responses. We previously characterized an S-locus RLK (CBRLK1) at the biochemical level. In this study, we examined the physiological function of CBRLK1 in defense responses. CBRLK1 mutant and CBRLK1-overexpressing transgenic plants showed enhanced and reduced resistance against a virulent bacterial pathogen, respectively. The altered pathogen resistances of the mutant and overexpressing transgenic plants were associated with increased and reduced induction of the pathogenesis-related gene PR1, respectively. These results suggest that CBRLK1 plays a negative role in the disease resistance signaling pathway in Arabidopsis.