Multivalent interactions essential for lentiviral integrase function.

Ballandras-Colas, Allison; Chivukula, Vidya; Gruszka, Dominika T.; Shan, Zelin; Singh, Parmit K.; Pye, Valerie E.; McLean, Rebecca K.; Bedwell, Gregory J.; Li, Wen; Nans, Andrea; Cook, Nicola J.; Fadel, Hind J.; Poeschla, Eric M.; Griffiths, David J.; Vargas, Javier; Taylor, Ian A.; Lyumkis, Dmitry; Yardimci, Hasan; Engelman, Alan N.; Cherepanov, Peter

A multimer of retroviral integrase (IN) synapses viral DNA ends within a stable intasome nucleoprotein complex for integration into a host cell genome. Reconstitution of the intasome from the maedi-visna virus (MVV), an ovine lentivirus, revealed a large assembly containing sixteen IN subunits1. Herein, we report cryo-EM structures of the lentiviral intasome prior to engagement of target DNA and following strand transfer, refined at 3.4 and 3.5 Å resolution, respectively. The structures elucidate details of the protein-protein and protein-DNA interfaces involved in lentiviral intasome formation. We show that the homomeric interfaces involved in IN hexadecamer formation and the α-helical configuration of the linker connecting the C-terminal and catalytic core domains are critical for MVV IN strand transfer activity in vitro and for virus infectivity. Single-molecule microscopy in conjunction with photobleaching reveals that the MVV intasome can bind a variable number, up to sixteen molecules, of the lentivirus-specific host factor LEDGF/p75. Concordantly, ablation of endogenous LEDGF/p75 results in gross redistribution of MVV integration sites in human and ovine cells. Our data confirm the importance of the expanded architecture observed in cryo-EM studies of lentiviral intasomes and suggest that this organization underlies multivalent interactions with chromatin for integration targeting to active genes. The authors determined high-resolution cryo-EM structures of the lentiviral intasome — the nucleoprotein complex that inserts viral DNA into a host chromosome — and show that the architecture comprising 16 integrase subunits is critical for its function.

RETROVIRUS diseases; VIRAL DNA; NEUROTROPHIN receptors; CATALYTIC domains; CHROMOSOMES; GENE targeting; CHROMATIN

Nature Communications, 2022, Vol 13, Issue 1, p1

2041-1723

Academic Journal

10.1038/s41467-022-29928-8