Embryonal histone H1 subtypes of the sea urchin Strongylocentrotus purpuratus: purification, characterization, and immunological comparison with H1 subtypes of the adult.

The four H1 subtypes utilized during embryonic development of Strongylocentrotus purpuratus were purified. Their amino acid compositions and immunological reactivities show that they have different primary structures. Antisera against them were used to identify the H1 subtypes present in adult tissues. These experiments revealed that adult tissues do not contain detectable levels of the two H1 subtypes expressed in the earliest embryonic stages (H1 cs and H1 alpha) but do contain the two subtypes expressed from the blastula stage on (H1 beta and H1 gamma). In addition, all adult tissues examined contain H1 lambda, a subtype of unusually low apparent molecular weight, which is not found in the embryo prior to the feeding larval stage and is not closely related immunologically to any of the embryonal H1 subtypes.