| Carnevale, Mingarelli, Malpuech, and Michel’s (3MC) syndrome is an autosomal
recessive developmental disorder in humans caused by a mutation in the MASP1 gene that
encodes mannan-binding lectin serine protease 1 (MASP1), an enzyme associated with the lectin
complement pathway of the innate immune system. Patients with this syndrome present with
craniofacial dysmorphia and learning disabilities, phenotypes that indicate a role for MASP1
during embryonic development, however, the function of MASP1 during development is still
unclear. To bridge this knowledge gap, we genetically manipulated Xenopus laevis embryos via
microinjections with either in vitro transcribed masp1 mRNA (overexpression) or morpholino
(MO, knockdown). Craniofacial and neural structures both arise from cells of the ectoderm,
therefore we performed in situ hybridization (ISH) on control and injected embryos from
multiple developmental stages to get a dynamic picture of how masp1 manipulation impacts
multiple ectodermal cell populations. We discovered that ectodermal patterning along with neural
crest cell migration was disrupted. Masp1 acts as a protease that initiates a protein cleavage
cascade in the immune system, however it is unclear whether this domain functions during early
development. Using site-directed mutagenesis, we generated a protease dead masp1 mRNA and
microinjected it into X. laevis embryos. Through subsequent phenotype assessment, we
discovered that Masp1 is functioning as a protease during development. These results increase
our knowledge of how MASP1 mutation leads to phenotypes present in those experiencing 3MC
syndrome and potentially why multiple tissue types are affected.
Keywords: 3MC syndrome, MASP1, Xenopus laevis, Ectodermal Patterning, Neural Cre |