RESUMO
We have studied two regions of Dictyostelium discoideum chromatin and identified several DNase I-hypersensitive sites in these regions. One of these sites is located about 300 to 500 bases upstream of the transcriptional start site of a gene that is expressed at all stages of development. This site is present in both vegetative cells and postaggregation cells. Another hypersensitive site is associated with a gene that is expressed only after the multicellular stage. This site is located about 400 bases upstream of the start site, and it is present only in postaggregation cells. Thus, much like higher eucaryotes, D. discoideum contains DNase I-hypersensitive sites that may be involved in the regulation of the genes with which they are associated.
Assuntos
Cromatina/ultraestrutura , DNA Fúngico/genética , Dictyostelium/genética , Diferenciação Celular , Mapeamento Cromossômico , Desoxirribonuclease I , Dictyostelium/crescimento & desenvolvimento , Regulação da Expressão Gênica , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Transcrição GênicaRESUMO
The complete nucleotide sequence of HPV16 DNA (7904 bp) cloned from an invasive cervical carcinoma was determined. Homology comparisons allowed us to align the major open reading frames with the other published papilloma virus DNA sequences. The general organization of the open reading frames is similar to that of the other four papillomavirus (BPV1, HPV1a, HPV6b, CRPV) already sequenced. The sequence reveals an interruption of the reading frame coding for a suspected E1 protein.
Assuntos
DNA Viral , Papillomaviridae/genética , Sequência de Bases , Clonagem Molecular , Códon , Enzimas de Restrição do DNA , DNA Viral/genética , Humanos , Biossíntese de Proteínas , Proteínas Virais/genéticaRESUMO
Mouse L fibroblasts and other mammalian cells are killed by the translation inhibitor hygromycin B. We have modified the gene conferring resistance against hygromycin B in E. coli in such a way that it can be transcribed in mammalian cells from the promoter of the HSVtk gene. The resulting plasmid, pHMR272, was transfected into mouse L fibroblasts and HeLa cells by the calcium phosphate method and upon selection produced clones resistant against hygromycin B. The transfection rate was similar to that obtained with other selective markers. This plasmid is a useful addition to the relatively small number of dominant selectable markers available for mammalian cells.
