The invention in principle pertains to the field of recombinant manufacture of alkaloids and, in particular, cycloclavine. It provides polynucleotides for the gene cluster of enzymes involved in the biosynthesis of cycloclavin as well as vectors and host cells comprising such polynucleotides. Also provided are polypeptides encoded by the said polynucleotides which can be applied in a method for the manufacture of cycloclavine also encompassed by the present invention.