Details

Autor(en) / Beteiligte

• Kenyon, Lawrence Charles

Titel

Detection, characterization, and partial purification of two novel, sequence-specific DNA binding proteins

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

1990

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• Two novel DNase I hypersensitive site associated, sequence-specific DNA binding proteins were detected adjacent to the common proviral integration site of three previously isolated differentiation defective retroviral insertion mutants of Murine Erythroleukemia Cells (MEL cells). One hypersensitive site (HS1) was present only in induced MEL cells whereas the other (HS2) was present in both induced and uninduced MEL cells. An electrophoretic retardation assay was employed to detect specific proteins which bound at HS1 (HS1bp) and HS2 (HS2bp). HS1bp and HS2bp binding activities were present in nuclear extracts of uninduced and induced MEL cells, in nuclear extracts of other mouse cell lines, and in those of rat and human cell lines. Methylation interference of binding assays revealed that the HS2bp binding sequence was uncharacteristically large. Although segments of the binding sequences of both HS1bp and HS2bp share homology with those of known transcription factors, both binding sequences appear to be unique. No polymerase II promoter, enhancer, silencer or transcription termination activity could be identified for either HS1bp or HS2bp. HS1 and HS2 were also unable to function as replication origins. HS1bp was partially purified and identified as an 85Kd protein. HS2bp was partially purified but its molecular weight could not be determined. The possible role of the locus of integration and of HS1bp and HS2bp in the differentiation of MEL cells is discussed.