Harris, Henry (1925- )

Australian-born British geneticist known for his somatic cell-fusion experiments and his theory that genes are activated by molecules in the cytoplasm (the part of the cell that is outside the nucleus).

Transcription and translation of genes Harris examined the nature of the factors controlling cell differentiation (the process by which cells become increasingly specialized for different functions) and cell activity by fusing somatic (body) cells to form hybrid cells in which both the cytoplasm and the nuclei were fused. He then showed that when two very different cells were fused, the hybrid cell displayed the characteristics of both cells, indicating that their respective genes remained active so long as activating factors from their respective cytoplasm were present.

He suggested that genes could be controlled either at the level of transcription (DNA copying into RNA) in the nucleus or at the level of translation (protein production) in the cytoplasm after the messenger RNA (mRNA) has been exported from the nucleus.

In one particular experiment he elegantly showed that once mRNA is formed and exported to the cytoplasm, the control mechanism for translation is then in the cytoplasm. If transcription is blocked by the antibiotic actinomycin D, mammalian cells continue to synthesize specific proteins for long periods in culture. Gene expression is now known to be controlled both at the level of transcription and translation.

Life Harris graduated from the University of Sydney before studying for his PhD at Oxford University 1954. He worked at the Sir William Dunn School of Pathology at Oxford until 1959 and then became professor of cell biology at the John Innes Institute 1960. He moved back to Oxford 1963 to take up the chair in pathology and was elected a Fellow of the Royal Society 1968 and Regius professor of medicine at Oxford 1979.