Ribosomal protein L31 gene is a component of the 60S large ribosomal subunit encoded by
RPL31 gene, while
ribosomal protein L31 (
RPL31) is an important constituent of
peptidyltransferase center. In our research, the
cDNA and the genomic sequence of
RPL31 were cloned successfully from the giant panda (Ailuropoda melanoleuca) using RT-PCR technology respectively, following sequencing and analyzing preliminarily. We constructed a recombinant expression vector contained
RPL31 cDNA and over-expressed it in Escherichia coli using pET28a plasmids. The expression product was purified to obtain
recombinant protein of
RPL31 from the giant panda.
Recombinant protein of
RPL31 obtained from the experiment acted on human laryngeal
carcinoma Hep-2 and human
hepatoma HepG-2 cells for study of its anti-
cancer activity by MTT [3-(4, 5-dimehyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium
bromide] method. Then observe these cells growth depressive effect. The result indicated that the
cDNA fragment of the
RPL31 cloned from the giant panda is 419 bp in size, containing an open reading frame of 378 bp, and deduced
protein was composed of 125
amino acids with an estimated molecular weight of 14.46-kDa and PI of 11.21. The length of the genomic sequence is 8,091 bp, which was found to possess four exons and three introns. The
RPL31 gene can be readily expressed in E.coli, expecting 18-kDa
polypeptide that formed inclusion bodies.
Recombinant protein RPL31 from the giant panda consists of 157
amino acids with an estimated molecular weight of 17.86 kDa and PI of 10.77. The outcomes showed that the cell growth inhibition rate in a time- and dose-dependent on
recombinant protein RPL31. And also indicated that the effect at low concentrations was better than high concentrations on Hep-2 cells, and the concentration of 0.33 μg/mL had the best rate of growth inhibition, 44 %. Consequently, our study aimed at revealing the
recombinant protein RPL31 anti-
cancer function from the giant panda, providing scientific basis and resources for the research and development of
cancer protein drugs anti-
cancer mechanism research. Further studies of the mechanism and the signal transduction pathways are in progress.