Contacts between heterogeneous nuclear RNA (hnRNA) and protein in nuclear ribonucleoprotein particles have been photochemically crosslinked in intact HeLa or Friend erythroleukemia cell by irradiation with 254-nm light at doses of 10(1) to 10(5) ergs/mm2 (1 to 10(4) microJ/mm2). The resulting crosslinked particles were isolated and compared with conventional hnRNA . protein (hnRNP) preparations...

Mutation or deletion of one of the two genes encoding a protein known as SMN has recently been shown to cause spinal muscular atrophy. The SMN protein has been found to be part of a multi-component complex that appears to function in the assembly of cellular ribonucleoprotein particles.