DNA methylation is an epigenetic mark affecting genes and transposons. Screening for mutants that fail to establish DNA methylation yielded two we termed “involved in de novo” (idn) 1 and 2. IDN1 encodes DMS3, an SMC-related protein, and IDN2 encodes a previously unknown double-stranded RNA–binding protein with homology to SGS3. IDN1 and IDN2 control de novo methylation and small interfering RN...

It is hard and getting harder to strike a satisfying balance in teaching. Time dedicated to student-generated models or ideas is often sacrificed in an effort to "get through the syllabus." I describe a series of RNA interference (RNAi) experiments for undergraduate students that simultaneously explores fundamental concepts in gene regulation, develops cutting-edge laboratory skills, and embrac...

RNAs bearing various 2'-modifications have been synthesized in an effort to improve nuclease resistance. However, the gene silencing activity of small interfering RNAs (siRNAs) has been decreased or sometimes completely suppressed by the chemical modifications. We previously developed a post-synthetic approach for the synthesis of 2'-O-methyldithiomethyl-modified RNA, which can be converted int...

The gene silencing effect of short interfering RNA (siRNA) is known to vary strongly with the targeted position of the mRNA. A number of hypotheses have been suggested to explain this phenomenon. We would like to test if this positional effect is mainly due to the secondary structure of the mRNA at the target site. We proposed that this structural factor can be characterized by a single paramet...

Small interfering RNA silences specific genes by interfering with mRNA translation, and acts to modulate or inhibit specific biological pathways; a therapy that holds great promise in the cure of many diseases. However, the naked small interfering RNA is susceptible to degradation by plasma and tissue nucleases and due to its negative charge unable to cross the cell membrane. Here we report a n...

Hepatocyte growth factor/scatter factor-Met signaling has been implicated in tumor growth, invasion, and metastasis. Suppression of this signaling pathway by targeting the Met protein tyrosine kinase may be an ideal strategy for suppressing malignant tumor growth. Using RNA interference technology and adenovirus vectors carrying small-interfering RNA constructs (Ad Met small-interfering RNA) di...

Aquaporin 3 (AQP3) and phospholipase D2 (PLD2) are abnormally expressed and/or localized in squamous cell carcinoma (SCC). AQP3 transports glycerol to PLD2 for the synthesis of lipid second messenger, which can mediate the effect of the AQP3/PLD2 signaling module in the regulation of keratinocyte proliferation and differentiation. However, the role of the AQP3/PLD2 signaling module in the patho...