Dynamic expression of MMP28 during cranial morphogenesis.

Matrix metalloproteinases (MMPs) are a large family of proteases comprising 24 members in vertebrates. They are well known for their extracellular matrix remodelling activity. MMP28 is the latest member of the family to be discovered. It is a secreted MMP involved in wound healing, immune system maturation, cell survival and migration. MMP28 is also expressed during embryogenesis in human and mouse. Here, we describe the detailed expression profile of MMP28 in Xenopus laevis embryos. We show that MMP28 is expressed maternally and accumulates at neurula and tail bud stages specifically in the cranial placode territories adjacent to migrating neural crest cells. As a secreted MMP, MMP28 may be required in neural crest-placode interactions. This article is part of a discussion meeting issue 'Contemporary morphogenesis'.