FIG. 7.

Transmission EM images of negatively stained tubes assembled from HIV-1 CANC and ΔProCANC proteins. (A) Tubes formed from nucleic acid-free CANC. (B) Tubes assembled from CANC protein and bacteriophage MS2 RNA at a ratio of 10:1 (wt/wt). (C) Nucleic acid-free ΔProCANC particles. (D) Particles assembled from ΔProCANC and bacteriophage MS2 RNA at a ratio of 10:1 (wt/wt). All assembly reactions were performed as mentioned in Materials and Methods. Predominantly tubes were observed for CANC both in the presence and the absence of nucleic acids (no spheres were observed, and occasional cores did not exceed 1%). Nucleic acid-free ΔProCANC particles assembled variable numbers of core-like structures (∼20 to 50%) versus tubes. Particles assembled from ΔProCANC and bacteriophage MS2 RNA assembled a majority of tubes as well as about 1% spheres and ∼10 to 40% core-like structures. Approximately 70% and 80% of CANC protein was efficiently assembled into particles without or in the presence of MS2 RNA, respectively. For ΔProCANC, approximately 80% and 90% of protein was efficiently assembled into particles without or with addition of MS2 RNA, respectively. Bar, 100 nm.