IID-IN mutants exhibit normal viral protein processing encapsidation of RT and IN into virions: A and B. Immunoblot analysis of intracellular viral proteins. 50 ug of total protein from 293 T producer cells transfected with HIV-1NL4-3 WT or IID-IN mutants were separated on a 15% SDS-PAGE gel and transferred to nitrocellulose. The blots were probed with human patient sera. C. Immunoblot analysis of incorporation of viral proteins. Total protein lysates from 350 ng (p24) of HIV-1NL4-3 WT or mutant virions were separated by SDS-PAGE, transferred onto nitrocellulose and probed for the presence of IN, RT, and p24 using antibodies specific to each protein. D. Immunoblot analysis to determine the levels of endogenous INI1 in cells expressing IID-IN mutant viruses. Total protein from 293 T producer cells transfected with HIV-1NL4-3 WT or IID-IN mutants were probed with α-INI1 antibodies. The same blot was probed with α-GAPDH antibody as loading control.