Objective    To clone mouse sperm Sp17 gene and fulfill its expression in

E. coli

BL21(DE3).     Methods    The coding sequence of mouse protein Sp17 was amplified from mouse testis RNA through reverse transcription-polymerase chain reaction (RT-PCR)

and subsequently cloned into pET-28a (+). Recombinant Sp17 was then expressed in

E. coli

BL21 (DE3) with induction of IPTG and analyzed by SDS-PAGE and Western blotting. The mice were immunized intranasally with the recombinant proteins and the titers of specific antibodies IgG in serum were dete

cted.     Results    Sequencing and restriction digestion of the recombinant plasmid demonstrated that the coding sequence of mouse protein Sp17 was successfully cloned. SDS-PAGE and Western blot analysis showed that a recombinant protein with molecular weight of 24 000

which is corresponding to the theoretical molecular weight of Sp17 protein

existed in the extract of

E. coli

BL21 (DE3) cells. After immunization

Sp17-specific antibody IgG response was present in the mice.     Conclusion    The coding sequence of mouse Sp17 was cloned into pET-28a (+) plasmid vector

and high level of recombinant Sp17 protein expressed in

E. coli

BL21 (DE3) was obtained. The recombinant Sp17 protein can induce Sp17-specific antibody IgG response.