Expression of a mouse long terminal repeat is cell cycle-linked

The expression of the long terminal repeat (LTR) of intracisternal A particle retroviral sequences which are endogenous to the mouse genome has been shown to be linked to the early G₁ phase of the cell cycle in Friend erythroleukemia cells synchronized by density arrest and also in logarithmically growing cells fractionated into cell-cycle compartments by centrifugal elutriation. Regions of homology were found in comparing the LTR sequence to a repetitive Syrian hamster sequence specifically expressed in early G₁ in hamster cells.