Nuclear localization

Figure 5 shows that wild type and mutant E1A proteins localized to the nucleus in all of the constructs examined, consistent with the presence in each of a C-terminal nuclear localization site.

Figure 5 Cellular localization of E1A proteins. Growing cultures of MSY596 were transferred to media containing 2% galactose for four hours to express E1A proteins, and then plated on glass cover slips. Identical fields were analyzed by phase contrast microscopy (Cells), indirect immunofluorescence using the anti-E1A monoclonal antibody M73 and FITC conjugated anti-IgG as stain (E1A), and fluorescence microscopy using 4',6-Diamidino-2-phenylindole-dihydrochloride as stain (DNA). (A) E1A289; (B) E1A243; (C) dl1101; (D) dl1103; (E) dl1104

Cells expressing E1A243 and dl1101 also showed increased cytoplasmic staining relative to the other derivatives; increased cytoplasmic staining with E1A243 has been noted previously (73). These results show that the loss of function seen with E1A243, and with dl1101, dl1103, and dl1104, can not be due to an absence of nuclear E1A protein. Therefore, we conclude that the inhibition of growth in G1 caused by expression of E1A proteins in S. cerevisiae depends on the N-terminal region, CR1, and CR3.


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November 26, 1995 at 9:52 PM