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In situ Subcellular Fractionation of Adherent and Non-adherent Mammalian Cells
Published on: July 24, 2010
Identification and characterization of the CRPV E7 protein expressed in COS-7 cells
1Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024.
Abstract:
The papillomavirus E7 protein may play an important role in oncogenesis as it is the major viral protein present in human cervical cancer-derived cell lines. Because of the relevance of the cottontail rabbit papillomavirus (CRPV) system for the study of viral-induced malignancies, we characterized its E7 protein expressed by a heterologous strong promoter. An E7-specific antiserum was obtained by immunizing rabbits with a Trp E-E7 fusion protein containing the 88 carboxyl-terminal amino acids of E7. This antiserum specifically precipitated from [35S]cysteine but not from 32PO4-labeled transiently transfected COS-7 cells a 14-kDa protein. The protein was present only in the soluble cytoplasmic fraction and exhibited a heterogeneous sedimentation rate in nondenaturing glycerol gradients.
