Aspects of the regulation of histone genes.

Sequencing of cloned histone DNA of the sea urchin Psammechinus miliaris has confirmed the map of the histone genes obtained earlier by rather less refined techniques. Sequencing of spacer has revealed that it is unlikely to code for protein. Some interesting sequences in the prelude regions to the structural genes have been found. The technique of injecting DNA into the germinal vesicle of the Xenopus oocyte has been greatly simplified, so that now many of the parameters governing the transcription of the injected genes can be investigated. Some mRNA-like molecules appear when circular histone DNA is inserted into the oocyte nucleus. We are cautiously optimistic that the technique can be further developed and will provide a useful tool for the study of the molecular mechanisms governing the expression of structural genes coding for proteins.