Genetics + Genomics

Although the genome editing system known as CRISPR/Cas has revolutionized genetic research in cell lines, its overall efficiency has been relatively poor when used to generate genetically altered animals for disease modeling.  Now Whitehead Institute scientists have altered the approach in a manner that could accelerate the production of mice carrying precise mutations of multiple genes.

A team of Whitehead Institute scientists has discovered the surprising manner in which an enigmatic protein known as SUUR acts to control gene copy number during DNA replication. It’s a finding that could shed new light on the formation of fragile genomic regions associated with chromosomal abnormalities.  

Scientists have long theorized that the way in which the roughly three meters of DNA in a human cell is packaged to fit within a nuclear space just six microns wide, affects gene expression. Now, Whitehead Institute researchers present the first evidence that DNA structure does indeed have such effects—in this case finding a link between chromosome structure and the expression and repression of key genes.

Deploying sophisticated high-throughput sequencing technology, dubbed ψ-seq, a team of Whitehead Institute and Broad Institute researchers collaborated on a comprehensive, high-resolution mapping of ψ sites that confirms pseudouridylation, the most common post-transcriptional modification, does indeed occur naturally in mRNA.

The protein CENP-A, which is integrated into human DNA at the centromere on each chromosome, has a vital role in cell division. Work from Whitehead Institute Member Iain Cheeseman’s lab describes how the vital and tightly controlled replenishment of CENP-A progresses.

The lab of Whitehead Member Terry Orr-Weaver has conducted perhaps the most comprehensive look yet at changes in translation and protein synthesis during a developmental change, using the oocyte-to-embryo transition in Drosophila as a model system. One of the insights from this research is that a surprisingly large number of mRNAs that are translationally regulated.

Whitehead Institute researchers have identified a potential dual-pronged approach to treating Niemann-Pick type C (NPC) disease, a rare but devastating genetic disorder. By studying nerve and liver cells grown from NPC patient-derived induced pluripotent stem cells (iPSCs), the scientists determined that although cholesterol does accumulate abnormally in the cells of NPC patients, a more significant problem may be defective autophagy—a basic cellular function that degrades and recycles unneeded or faulty molecules, components, or organelles in a cell. Here, the scientists propose two drugs, one to reduce cholesterol buildup and the other to induce autophagy, as a strategy for treating NPC.

Whitehead Institute scientists have identified a genetic cause of a facial disorder known as hemifacial microsomia (HFM). The researchers find that duplication of the gene OTX2 induces HFM, the second-most common facial anomaly after cleft lip and palate.