Detection of mRNA encoding an antibacterial-metalloprotein (MPII) by in situ hybridization with a cDNA probe generated by polymerase chain reaction in the worm Nereis diversicolor.

Based on partial amino acid sequence of an antibacterial-metalloprotein (MPII) consisting of a N-terminal fragment (1-33th) and an 43 amino acids long internal fragment, two oligonucleotides primers were synthesized and used to generate a cDNA fragment by the PCR method. The specificity of the PCR synthesized 220 bp fragment was verified by hybrid-arrest translation and sequencing. In situ hybridization performed with this cDNA fragment on Nereis diversicolor whole body defined two specific sites of recognition: a cluster of cells floating in the coelom and two types of muscles (perineural and oblique). Finally, the chronological expression of the MPII was postulated.