PROTEIN SYNTHESIS IN THE POLAR LOBE AND LOBELESS EGG OF ILYANASSA OBSOLETA

¹ Biology Department, Brooklyn College, Brooklyn, N. Y. 11210

The relative rates of protein synthesis in the lobeless egg and polar lobe of Ilyanassa obsoleta were measured and found to be the same. Two-dimensional electrophoresis of ³⁵S-methionine in vivo labeled polypeptides extracted from the Ilyanassa egg and its isolates resolved the same set of polypeptides from the egg, lobeless egg, and isolated polar lobe. For those peptides detected it was concluded that (1) the lobeless egg and the polar lobe contain the same set of mRNAs, (2) these mRNAs are not differentially translated in either of these isolates, (3) the polar lobe does not regulate the synthesis of these proteins, either quantitatively or qualitatively, during early cleavage, and (4) the peptides synthesized in the isolated polar lobe were translated from mRNAs produced during oogenesis.

It was shown by one-dimensional electrophoresis of ³⁵S-methionine-labeled basic peptides that the egg, lobeless egg, and isolated polar lobe synthesized, at approximately the same rate, two variants of H1 histone, histones H2A, H2B, H3, and H4, and high mobility group peptides 14 and 17. Because these peptides were synthesized in the isolated polar lobe it was concluded that they were translated from maternal mRNAs.