Lin-28 is an RNA-binding protein that is known for its role in promoting the pluripotency of stem cells. In the present study, Arabian camel Lin-28 (cLin-28) cDNA was identified and analyzed. Full length cLin-28 mRNA was obtained using the reverse transcription polymerase chain reaction (RT-PCR). It was shown to be 715 bp in length, and the open reading frame (ORF) encoded 205 amino acids. The molecular weight and theoretical isoelectric point (pI) of the cLin-28 protein were predicted to be 22.389 kDa and 8.50, respectively. Results from the bioinformatics analysis revealed that cLin-28 has two main domains: an N-terminal cold-shock domain (CSD) and a C-terminal pair of retroviral-type Cysteine3Histidine (CCHC) zinc fingers. Sequence similarity and phylogenetic analysis showed that the cLin-28 protein is grouped together Camelus bactrianus and Bos taurus. Quantitative real-time PCR (qPCR) analysis showed that cLin-28 mRNA is highly expressed in the lung, heart, liver, and esophageal tissues. Peptide mass fingerprint-mass spectrometry (PMF-MS) analysis of the purified cLin-28 protein confirmed the identity of this protein. Comparing the modeled 3D structure of cLin-28 protein with the available protein 3D structure of the human Lin-28 protein confirmed the presence of CSD and retroviral-type CCHC zinc fingers, and high similarities were noted between the two structures by using super secondary structure prediction.
Keywords: 3D structure; Arabian Camel; Lin-28; PMF-MS; bioinformatics analysis; cold-shock domain (CSD); phylogenetic analysis.