Can limb regeneration be induced? Few have pursued this question, and an evolutionarily conserved strategy has yet to emerge. This study reports a strategy for inducing regenerative response in appendages, which works across three species that span the animal phylogeny. In Cnidaria, the frequency of appendage regeneration in the moon jellyfish was increased by feeding with the amino acid L-leucine and the growth hormone insulin. In insects, the same strategy induced tibia regeneration in adult . Finally, in mammals, L-leucine and sucrose administration induced digit regeneration in adult mice, including dramatically from mid-phalangeal amputation. The conserved effect of L-leucine and insulin/sugar suggests a key role for energetic parameters in regeneration induction. The simplicity by which nutrient supplementation can induce appendage regeneration provides a testable hypothesis across animals.
The cGAS-STING pathway plays essential roles in detecting cytosolic dsDNA and initiating antiviral and antibacterial responses in vertebrates. However, knowledge about its function in antiviral response of invertebrates is very limited. In the present study, a gene encoding a Mab21-containing protein, a cGAS homologue, was identified from a decapod crustacean Litopenaeus vannamei and designated as LvMab21cp. LvMab21cp was mainly distributed in intestine and hepatopancreas, showing similar expression profile with other genes in the cGAS-STING pathway, such as LvSTING and LvIRF. The expression levels of LvMab21cp, LvSTING and LvIRF were up-regulated in intestine and hepatopancreas of shrimp after white spot syndrome virus (WSSV) infection. Knockdown of LvMab21cp by dsRNA-mediated RNA interference could decrease the expression levels of its putative downstream genes, including LvSTING, LvIRF, LvVago4 and LvVago5, and enhance the in vivo propagation of WSSV in shrimp. Overexpression of LvMab21cp and LvSTING in HEK 293T cells activated the expression of mammalian IFNs upon simulation with interferon stimulatory DNA (ISD). These data suggest that LvMab21cp was a cGAS homologue, a member of the shrimp cGAS-STING pathway, and play an important role during WSSV infection. To our knowledge, this is the first report to show the role of the cGAS-STING pathway in the antiviral response of invertebrates, which will provide new insights into the innate immunity of invertebrates.
Unlike in mice, multinucleated blastomeres appear at a high frequency in the two-cell-stage embryos in humans. In this Point of View article, we demonstrate that the first mitotic spindle formation led by sperm centrosome-dependent microtubule organizing centers may cause a high incidence of zygotic division errors using human tripronuclear zygotes.