Chi-kong Lau

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Intrinsic immune responses autonomously inhibit viral replication and spread. One pathway that restricts viral infection in plants and insects is RNA interference (RNAi), which targets and degrades viral RNA to limit infection. To identify additional genes involved in intrinsic antiviral immunity, we screened Drosophila cells for modulators of viral(More)
Here we identify a component of the nuclear RNA cap-binding complex (CBC), Ars2, that is important for miRNA biogenesis and critical for cell proliferation. Unlike other components of the CBC, Ars2 expression is linked to the proliferative state of the cell. Deletion of Ars2 is developmentally lethal, and deletion in adult mice led to bone marrow failure(More)
BACKGROUND Splicing of pre-mRNA in eukaryotes imprints the resulting mRNA with a specific multiprotein complex, the exon-exon junction complex (EJC), at the sites of intron removal. The proteins of the EJC, Y14, Magoh, Aly/REF, RNPS1, Srm160, and Upf3, play critical roles in postsplicing processing, including nuclear export and cytoplasmic localization of(More)
The survival of motor neurons protein (SMN) is part of a large complex that contains six other proteins, Gemins2-7. The SMN complex assembles the heptameric Sm protein core on small nuclear RNAs (snRNAs) and plays a critical role in the biogenesis of snRNPs, the major and essential components of mRNA splicing in eukaryotes. For its function, the SMN complex(More)
Gemin5 binds specifically to the small nuclear RNA (snRNA)-defining small nuclear ribonucleoprotein (snRNP) code sequence and is essential, together with other components of the survival of motor neurons (SMN) complex, for the biogenesis of snRNPs, the major constituents of spliceosomes. We show that this binding is mediated by Gemin5's WD repeat domain, a(More)
The three-dimensional structures of brain pyridoxal kinase and its complex with the nucleotide ATP have been elucidated in the dimeric form at 2.1 and 2.6 A, respectively. Results have shown that pyridoxal kinase, as an enzyme obeying random sequential kinetics in catalysis, does not possess a lid shape structure common to all kinases in the ribokinase(More)
The bacteriophage P1 Cre recombinase catalyzes site-specific recombination between 34-base-pair loxP sequences in a variety of topological contexts. This reaction is widely used to manipulate DNA molecules in applications ranging from benchtop cloning to genome modifications in transgenic animals. Despite the simple, highly symmetric nature of the Cre-loxP(More)
Protein-DNA bindings between transcription factors (TFs) and transcription factor binding sites (TFBSs) play an essential role in transcriptional regulation. Over the past decades, significant efforts have been made to study the principles for protein-DNA bindings. However, it is considered that there are no simple one-to-one rules between amino acids and(More)
The diagnosis of glycogen storage disease (GSD) type IX is often complicated by the complexity of the phosphorylase kinase enzyme (PHK), and molecular analysis is the preferred way to provide definitive diagnosis. Here we reported two novel mutations found in two GSD type IX patients with different residual enzyme activities from Hong Kong, China using(More)
Pyridoxal kinase (ATP:pyridoxal 5'-phosphotransferase; EC 2.7.1.35) is a key enzyme in the transformation of vitamin B(6) to pyridoxal-5'-phosphate. Pyridoxal-5'-phosphate is the crucial cofactor required by numerous enzymes involved in the metabolism of amino acids and the synthesis of many neurotransmitters. Pyridoxal kinase from sheep brain was(More)