Cloning and expression of a novel cDNA encoding shell coat protein, cp4, from the brushtail possum (Trichosurus vulpecula)

Abstract

The marsupial conceptus is enclosed by several egg coats of evolutionary significance and unknown composition, of which the shell coat in mammals occurs only in marsupials and monotremes. Intact coats are vital to marsupial embryonic development. Towards a better understanding of the marsupial coat proteins, a cDNA sequence (cp4) encoding a shell coat protein was cloned from the brushtail possum. A cDNA library of a zygote stage uterus was screened using a deduced oligonucleotide sequence based on a partial amino acid sequence of the coat protein. This study has confirmed a single copy cp4 gene encoding a unique protein of 306 amino acids, although its N-terminus shares high sequence identit..