Mz. Yang et al., A NOVEL MATRIX METALLOPROTEINASE GENE (XMMP) ENCODING VITRONECTIN-LIKE MOTIFS IS TRANSIENTLY EXPRESSED IN XENOPUS-LAEVIS EARLY EMBRYO DEVELOPMENT, The Journal of biological chemistry, 272(21), 1997, pp. 13527-13533
To study the role of matrix metalloproteinases (MMPs) in early vertebr
ate development, we cloned cDNAs for six different MMPs from the frog
Xenopus laevis embryos at different stages of development and describe
here a novel MMP called XMMP. Xenopus XMMP has 604 amino acids includ
ing a putative signal peptide of 22 residues. At the carboxyl-terminal
end of the propeptide, XMMP has a 37-amino acid-long insertion domain
containing a segment that is 38% identical with a rat vitronectin seq
uence between residues 108-135, Following this domain is an RRKR motif
, a putative cleavage site for intracellular activation by furin prote
inases, XMMP lacks a proline-rich linker peptide, or hinge region, typ
ically found in other MMPs between the catalytic domain and carboxyl-t
erminal ''hemopexin/vitronectin-like'' domain. In XMMP, the carboxyl-t
erminal domain is composed of four tandem repeats that are 21-33% iden
tical to a sequence (residues 213-264) encoded by vitronectin exon-5,
Interestingly, XMMP gene is transiently expressed during Xenopus embry
o development, XMMP mRNA of 3.0 kilobase pairs was undetected in the b
lastula stage embryo, induced in gastrula embryo, expressed in neurula
embryo, and then down-regulated in pretailbud embryo, In comparison,
other Xenopus MMP genes that we have cloned show a different developme
ntal regulation. In blastula embryo, the only MMP gene expressed was f
ound to be 92-kDa type IV collagenase, which was also expressed in the
gastrula, neurula, and pretailbud embryos. Expression of stromelysin-
1, stromelysin-3, and two different membrane type-MMPs was first detec
ted in the neurula and pretailbud embryos, These results suggest that
MMPs and the novel XMMP reported here play a role in Xenopus early dev
elopment.