The Abelson murine leukemia virus (Ab-MLV or A-MuLV) is a retrovirus (Class VI) used to induce malignant transformation of murine lymphoid cells.

As a retrovirus, it has a single-stranded, positive sense RNA genome which replicates via a DNA intermediate mediated by a reverse transcriptase.

[1] A-MuLV causes a rapidly progressive lymphosarcoma known as Abelson disease in mice, which is a type of leukemia that does not involve the thymus.

However, this is only possible when the host cell is co-infected with a helper virus which provides functions it needs to be able to replicate which it does not code for in its own genome such as a reverse transcriptase and some major structural proteins.

It causes leukemia directly by interfering with the normal growth and differentiation processes of lymphocytes.