Current Research and Scholarly Interests
I study non-coding sequence elements that regulate protein translation during mammalian development.
- Argonaute proteins CURRENT BIOLOGY 2011; 21 (12): R446-R449
Phosphate and R2D2 Restrict the Substrate Specificity of Dicer-2, an ATP-Driven Ribonuclease
2011; 42 (2): 172-184
Drosophila Dicer-2 generates small interfering RNAs (siRNAs) from long double-stranded RNA (dsRNA), whereas Dicer-1 produces microRNAs (miRNAs) from pre-miRNA. What makes the two Dicers specific for their biological substrates? We find that purified Dicer-2 can efficiently cleave pre-miRNA, but that inorganic phosphate and the Dicer-2 partner protein R2D2 inhibit pre-miRNA cleavage. Dicer-2 contains C-terminal RNase III domains that mediate RNA cleavage and an N-terminal helicase motif, whose function is unclear. We show that Dicer-2 is a dsRNA-stimulated ATPase that hydrolyzes ATP to ADP; ATP hydrolysis is required for Dicer-2 to process long dsRNA, but not pre-miRNA. Wild-type Dicer-2, but not a mutant defective in ATP hydrolysis, can generate siRNAs faster than it can dissociate from a long dsRNA substrate. We propose that the Dicer-2 helicase domain uses ATP to generate many siRNAs from a single molecule of dsRNA before dissociating from its substrate.
View details for DOI 10.1016/j.molcel.2011.03.002
View details for Web of Science ID 000289873700006
View details for PubMedID 21419681
Variation in the attachment of Streptococcus pneumoniae to human pharyngeal epithelial cells after treatment with S-carboxymethylcysteine.
Journal of infection and chemotherapy
2008; 14 (4): 333-336
S-carboxymethylcysteine (S-CMC) is a mucolytic agent that can prevent respiratory infection by decreasing the attachment of respiratory pathogens to human pharyngeal epithelial cells (HPECs). Streptococcus pneumoniae is a major cause of respiratory infections. A previous study revealed that treatment of S. pneumoniae with S-CMC caused a decrease in the attachment of this bacterium to HPECs. In the present study we found that the effect of S-CMC varied according to hosts and strains. S-CMC treatment altered the surface structure of S. pneumoniae, resulting in a decrease of attachment, without affecting the virulence of the bacteria.
View details for DOI 10.1007/s10156-008-0626-z
View details for PubMedID 18709541
- Turkish isolates of Helicobacter pylori belong to the Middle Eastern genotypes CLINICAL MICROBIOLOGY AND INFECTION 2006; 12 (1): 97-98