Cloning and Prokaryotic Expression of the plastoglobules protein gene from Haematococcus pluvialis

Carotenoids were organized in plastoglobules located in the interthylakoid space of the chloroplast for many plants. However, the plastoglobule, a carotenoid deposit structure in chromoplast, was not clear in Haematococcus pluvialis yet up to date. In the present study, many osmiophilic globuli appeared in both the chromoplast and cytoplasm of H. pluvialis under electron microscopy with a modified method. Those revealed clearly the presence of plastoglobules in the chloroplast of H. pluvialis. A full-length cDNA was isolated from H. pluvialis through a RT-PCR and RACE (rapid amplification of cDNA ends) method. And the completing cDNA encoded a protein which had high homology with the major component proteins of plastoglobules in many plants and was termed as HPGP (Haematococcus plastoglobules protein). Furthermore, this cDNA was expressed in the prokaryotic expression system, and the resultant fusion proteins with His-Tags were purified by immobilized metal affinity chromatography (IMAC). The polyclonal antibodies against the protein were raised in rabbits and the raw serum was collected without further purification. Those might provide an important basis for unraveling the function of the protein in the future.