The link between HIV-like viruses and LINE-1

Long ago, before retroviruses such as HIV existed, there were simpler genetic elements called retrotransposons. These are virus-like genetic elements inside the DNA of cells. They selfishly spread copies of themselves across the genome. If this happens in eggs or sperm, they can also be passed from parent to child. Today, retrotransposons make up a large part of human DNA

Retroviruses and retrotransposons are linked because both use an enzyme called reverse transcriptase. This enzyme copies RNA into DNA. Over time, retroviruses evolved from ancient retrotransposon-like elements, gaining the ability to move between individuals rather than only within a genome. Even though these enzymes have changed over millions of years, key parts stayed similar because they still do the same job

Some HIV medicines take advantage of this similarity. They are called nucleoside or nucleotide reverse transcriptase inhibitors (NRTIs). They look similar to normal DNA building blocks. When the enzyme uses one of these molecules by mistake, DNA copying stops too early. In HIV treatment, this helps block the virus from making DNA and inserting it into the cell's genome. NRTIs are very effective in HIV and can be used by patients for many years

Some NRTIs also inhibit LINE-1, a human retrotransposon that can reactivate in aging and cancer. However, they do not significantly inhibit other enzymes that use DNA building blocks. This makes LINE-1 a possible target for new therapies. But LINE-1 is only one factor in these diseases. L1 Therapeutics was founded to figure out when LINE-1 reactivation matters most, which patients might benefit, and how much blocking LINE-1 can help treat diseases of aging. Scientific advances, better diagnostics, and new technology (including AI) are now making this possible