Expression of a novel human retroviral NP9 gene and potential roles of its protein in systemic lupus erythematosus patients.

Objective: To investigate the expression of a novel retroviral (NP9) gene transcripts and the possible role of its protein in systemic lupus erythematosus (SLE) patients.
Methods: The retroviral NP9 gene in SLE patients was isolated and cloned using RT-PCR and TA cloning techniques, and it was analyzed by sequencing. The expression of the NP9 genes in 40 patients with SLE and 48 normal controls using RT-PCR was detected. NCBI BLAST and DNASIS 3.1 software were used to analyze the features of protein of NP9 gene.
Results: The positive ratio (77.5%) of the mRNA expression of the retroviral NP9 gene in SLE patients is significantly higher than that (8.3%) in normal subjects (P<0.01). The recombinant NP9 protein comprises 74 AA with pI 9.59. Amino acid sequence analysis indicates that the retroviral NP9 protein shares higher homologies with several human proteins with important biological functions.
Conclusion: SLE patients possess specific novel retroviral NP9 transcripts. The expression of the retroviral NP9 gene may involve in the genesis or development of SLE.