Molecular cloning and characterization of porcine ribosomal protein L21

Ribosomal protein L21 (RPL21) is a structural component of the 60S subunit of the eukaryotic ribosome. This protein has an important role in protein synthesis and the occurrence of hereditary diseases. Pig is a common laboratory model, however, to the best of our knowledge, its RPL21 gene has not been cloned to date. In this study, we cloned and identified the full-length sequence of the pig RPL21 gene for the first time. In addition, we examined its expression pattern and function by using overexpression or knockdown approaches. As a result, we obtained a 604 bp segment that contains a 483 bp open reading frame encoding 160 amino acids. The pig RPL21 gene is located in the “+” strand of chromosome 11, which spans 2167 bp from 4199792 to 4201958. Pig RPL21 protein has nine strands and two helices in its secondary structure. Pig RPL21 is predominantly expressed in ovary and lung, at lower levels in kidney, small intestine, and skin, and at the lowest levels in heart and liver. Furthermore, RPL21 expression is closely connected with cell proliferation and cell cycle arrest. The results are intended to provide useful information for the further study of pig RPL21.

Microtubule distribution in somatic cell nuclear transfer bovine embryos following control of nuclear remodeling type

This study was conducted to evaluate the microtubule distribution following control of nuclear remodeling by treatment of bovine somatic cell nuclear transfer (SCNT) embryos with caffeine or roscovitine. Bovine somatic cells were fused to enucleated oocytes treated with either 5 mM caffeine or 150 micrometer roscovitine to control the type of nuclear remodeling. The proportion of embryos that underwent premature chromosome condensation (PCC) was increased by caffeine treatment but was reduced by roscovitine treatment (p < 0.05). The microtubule organization was examined by immunostaining beta- and gamma-tubulins at 15 min, 3 h, and 20 h of fusion using laser scanning confocal microscopy. The gamma-tubulin foci inherited from the donor centrosome were observed in most of the SCNT embryos at 15 min of fusion (91.3%) and most of them did not disappear until 3 h after fusion, regardless of treatment (82.9-87.2%). A significantly high proportion of embryos showing an abnormal chromosome or microtubule distribution was observed in the roscovitine-treated group (40.0%, p < 0.05) compared to the caffeine-treated group (22.1%). In conclusion, PCC is a favorable condition for the normal organization of microtubules, and inhibition of PCC can cause abnormal mitotic division of bovine SCNT embryos by causing microtubule dysfunction.