Jang YJ et al. (1998) Journal of Biochemistry and Molecular Biology "Developmental regulation of Caenorhabditis elegans DNA topoisomerase-I expression."

Koo H-S, Jang YJ, Park HS, Lee JH

[Journal of Biochemistry and Molecular Biology, 1998]

The developmental regulation of Caenorhabditis elegans DNA topoisomerase I expression was examined using synchronized Caenorhabditis elegans cultures. Variations of the relative mRNA and protein levels of the enzyme during their development were measured by Northern and Western analyses, respectively. The mRNA level was the highest at the embryonic stage, decreasing rapidly to the one tenth level at the L1 stage, and then increasing by a few fold at the L4 and young adult stages. The protein level was the highest at the L1 stage, with gradual decreasing at the following stages until it showed a slight increase at the young adult stage. Based on our results of the expressional regulation, the possible roles of DNA topoisomerase I in the development of C. elegans are discussed.

Lee MH et al. (1998) Biochim Biophys Acta "Alternative splicing in the Caenorhabditis elegans DNA topoisomerase I gene."

Koo H-S, Jang YJ, Lee MH

[Biochim Biophys Acta, 1998]

5'-end cDNA fragments of the Caenorhabditis elegans DNA topoisomerase I gene were obtained by rapid amplification of the cDNA ends from C. elegans mRNAs. The presence of a SL1 sequence at the 5'-terminus of the cDNA sequence suggested trans-splicing of the pre-mRNA. By comparing the complete cDNA sequence with the genomic lambda DNA clones, the gene structure composed of five exons was established. Alternative splicing deleting the second exon was observed in the cDNA fragments obtained by a gene-specific reverse transcription followed by polymerase chain reactions. The shorter mRNA missing the second exon was expressed at all the developmental stages, while the full-length mRNA was present only in embryos.

Kim JS et al. (1996) Eur J Biochem "cDNA cloning, expression, and chromosomal localization of Caenorhabditis elegans DNA topoisomerase I."

Kim Y-C, Jang YJ, Koo H-S, Chung IK, Kim JS, Lee JH

[Eur J Biochem, 1996]

By screening Caenorhabditis elegans cDNA libraries, overlapping cDNA clones encoding DNA topoisomerase I were obtained. An open reading frame of 751 amino acids was found in 3.2-kb cDNA sequence. The open reading frame has 54% and 50% identities to the amino acid sequences of human and Drosophila melanogaster DNA topoisomerases I, respectively. Northern blot analysis showed the presence of an mRNA of 3.4 kb which suggests that the cDNA sequences is close to full length. The 72-kDa C-terminal polypeptide expressed in Escherichia coli cells showed catalytic DNA topoisomerase I activity. The DNA topoisomerase I gene was mapped to position 18 of chromosome I by screening polytene YAC plasmid DNAs.

Kim JH et al. (2014) Nat Commun "The condensin component NCAPG2 regulates microtubule-kinetochore attachment through recruitment of Polo-like kinase 1 to kinetochores."

Kim KT, Lee SJ, Kim KG, Shim J, Jang YJ, Bong SM, Lee BI, Yoon EK, Kim JH, Ji MJ, Kim YH, Jung Y, Lee C

[Nat Commun, 2014]

The early event of microtubule-kinetochore attachment is a critical stage for precise chromosome segregation. Here we report that NCAPG2, which is a component of the condensin II complex, mediates chromosome segregation through microtubule-kinetochore attachment by recruiting PLK1 to prometaphase kinetochores. NCAPG2 colocalizes with PLK1 at prometaphase kinetochores and directly interacts with the polo-box domain (PBD) of PLK1 via its highly conserved C-terminal region. In both humans and Caenorhabditis elegans, when NCAPG2 is depleted, the attachment of the spindle to the kinetochore is loosened and misoriented. This is caused by the disruption of PLK1 localization to the kinetochore and by the decreased phosphorylation of its kinetochore substrate, BubR1. In addition, the crystal structure of the PBD of PLK1, in complex with the C-terminal region of NCAPG2, (1007)VLS-pT-L(1011), exhibits structural conservation of PBD-phosphopeptides, suggesting that the regulation of NCAPG2 function is phosphorylation-dependent. These findings suggest that NCAPG2 plays an important role in regulating proper chromosome segregation through a functional interaction with PLK1 during mitosis.