Involvement of L(-)-rhamnose in sea urchin gastrulation. Part II: alpha-L-Rhamnosidase

作者：Liang Jing; Aleksanyan Heghush; Metzenberg Stan; Oppenheimer Steven B^*

来源：Zygote, 2016, 24(3): 371-377.

DOI：10.1017/S0967199415000283

• Archenteron development
• Innate immunity
• l-rhamnose
• Rhamnose-binding lectin
• alpha-L-Rhamnosidase
• Sea urchin gastrulation

The sea urchin embryo is recognized as a model system to reveal developmental mechanisms involved in human health and disease. In Part I of this series, six carbohydrates were tested for their effects on gastrulation in embryos of the sea urchin Lytechinus pictus. Only l-rhamnose caused dramatic increases in the numbers of unattached archenterons and exogastrulated archenterons in living, swimming embryos. It was found that at 30 h post-fertilization the l-rhamnose had an unusual inverse dose-dependent effect, with low concentrations (1-3 mM) interfering with development and higher concentrations (30 mM) having little to no effect on normal development. In this study, embryos were examined for inhibition of archenteron development after treatment with -l-rhamnosidase, an endoglycosidase that removes terminal l-rhamnose sugars from glycans. It was observed that the enzyme had profound effects on gastrulation, an effect that could be suppressed by addition of l-rhamnose as a competitive inhibitor. The involvement of l-rhamnose-containing glycans in sea urchin gastrulation was unexpected, since there are no characterized biosynthetic pathways for rhamnose utilization in animals. It is possible there exists a novel l-rhamnose-containing glycan in sea urchins, or that the enzyme and sugar interfere with the function of rhamnose-binding lectins, which are components of the innate immune system in many vertebrate and invertebrate species.

• 出版日期2016-6