Assuntos
Carcinoma Basocelular/genética , Neoplasias Faciais/genética , Síndrome do Hamartoma Múltiplo/genética , Mutação de Sentido Incorreto , Síndromes Neoplásicas Hereditárias/genética , Neoplasias Cutâneas/genética , Proteínas Supressoras de Tumor/genética , Enzima Desubiquitinante CYLD , Feminino , Humanos , Pessoa de Meia-Idade , Linhagem , Couro CabeludoRESUMO
Changes in gene expression occur during cold acclimation in a variety of plants including Arabidopsis thaliana L. (Heyn). Here we examine the cold-regulated expression of A. thaliana cor78. The results of gene-fusion experiments confirm the finding of Yamaguchi-Shinozaki and Shinozaki ([1993] Mol Gen Genet 236: 331-340) that the 5' region of cor78 has cis-acting regulatory elements that can impart cold-regulated gene expression. Further, histochemical staining experiments indicated that this cold-regulatory element(s) was active at low temperature throughout much of the plant including leaves, stems, roots, flower petals, filaments, and sepals. Time-course experiments indicated that the activity of the cor78 promoter in cold-acclimated plants was down-regulated quickly in response to noninducing temperatures and that the half-life of the cor78 transcripts was only about 40 min at normal growth temperature. Fusion of the entire transcribed region of cor78 to the cauliflower mosaic virus 35S promoter resulted in a chimeric gene that was constitutively expressed and displayed little if any posttranscriptional regulation in response to low temperature.
Assuntos
Arabidopsis/genética , Genes de Plantas , Aclimatação/genética , Arabidopsis/metabolismo , Sequência de Bases , Caulimovirus/genética , Clonagem Molecular , Temperatura Baixa , DNA/genética , Regulação da Expressão Gênica , Cinética , Dados de Sequência Molecular , Peso Molecular , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Distribuição Tecidual , Transcrição GênicaRESUMO
Pinus palustris has a greatly reduced need for light to initiate chloroplast development in comparison to angiosperms. Light is not required for chlorophyll synthesis in dark-grown Pinus palustris seedlings. However, embryos do not contain chlorophyll, and synthesis is limited to seedlings having cotyledon lengths between about 0.5 cm and 2.0 cm. The final amount of chlorophyll accumulated by dark-grown seedlings is about one fifth of that in light-grown seedlingsat the same stage. The major light-harvesting chlorophyll a/b-polypeptides of Photosystem II (LHC IIb) are absent in the embryos but begin to accumulate in seedlings of 0.5 cm cotyledon length, irrespective of the light conditions. Although dark-grown seedlings accumulate most of the pigmented complexes seen in light-grown seedlings, there are differences in the subunit structure of some of them. These findings suggest that the majority of the components of the photosynthetic membrane do not require light for induction of synthesis or assembly into complexes, but that the final forms seen in light-grown seedlings may require light.
