Maternal characteristics of hatching enzymes in hybrid sea urchin embryos

Temperature Sensitivity of a Hybrid between Two Species of Sea Urchin Differing in Thermotolerance

“…Furthermore, no relationship was also found between developmental time and egg size for S. droebachiensis eggs. The embryo of this species living around the San Juan Archipelago is acclimatized to the lower temperatures (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) or 14°C) than the other species of sea urchins inhabiting this area. The eggs of this species were confirmed to cleave much faster at 8"C, nearly the same rate as that at 10°C, and more slowly than D. excentricus eggs or at nearly the same rate as S. purpuratus eggs at 13°C (35, Fujisawa, unpublished data), although S. droebachiensis eggs are much larger (155-160 pm).…”

The specificity of sea urchin hatching enzyme (envelysin) places it in the mammalian matrix metalloproteinase family

“…During this period of slow progress major interest has focused on the regulation of gene expression and enzyme biosynthesis (Barrett & Angelo, 1969;Showman & Whiteley, 1980), as well as purification, crystallization (Yasumasu,196 l ) , and characterization. Investigations from the late 1960s through the late 1980s mainly by two groups, Barrett's and Hoshi's, laid the cornerstone for today's knowledge of the basic aspects of sea urchin HEz.…”

Early expression of a collagenase-like hatching enzyme gene in the sea urchin embryo.

“…Thus it has been argued that, as most of the proteins newly synthesized by the young embryo, the hatching enzyme was likely synthesized from a maternal mRNA stored in the unfertilized egg rather than from a zygotic message. This view was supported by experiments with RNA synthesis inhibitors (Terman and Gross, 1965) and with interspecific hybrids (Barrett and Angelo, 1969). Actually, studies with inhibitors were unreliable (Gross and Cousineau, 1963;Terman and Gross, 1965) and contradicted by experiments using the polyadenylation blocker cordycepin (Whiteley and Whiteley, 1975).…”

“…The hatching enzyme, as a model to study gene expression during early development, has unique features: it is one of the few identified proteins which is newly synthesized well before the gastrula stage, it has a tightly controlled transient appearance and it catalyses a major developmental step. It has been discussed for a long time whether the mRNA coding for this enzyme is a maternal message stored in the unfertilized egg or a zygotic transcript synthesized from the embryonic genome during cleavage stages, but no definitive conclusion was reached (Gross and Cousineau, 1963;Terman and Gross, 1965; Barrett and Angelo, 1969;Showman and Whiteley, 1980). Whilst its existence has been demonstrated for a long time (Ishida, 1936) the enzyme itself was poorly known, as an adequately purified preparation was lacking.…”