X

Quality Statement

Pacific Biosciences is committed to providing high-quality products that meet customer expectations and comply with regulations. We will achieve these goals by adhering to and maintaining an effective quality-management system designed to ensure product quality, performance, and safety.

X

Image Use Agreement

By downloading, copying, or making any use of the images located on this website (“Site”) you acknowledge that you have read and understand, and agree to, the terms of this Image Usage Agreement, as well as the terms provided on the Legal Notices webpage, which together govern your use of the images as provided below. If you do not agree to such terms, do not download, copy or use the images in any way, unless you have written permission signed by an authorized Pacific Biosciences representative.

Subject to the terms of this Agreement and the terms provided on the Legal Notices webpage (to the extent they do not conflict with the terms of this Agreement), you may use the images on the Site solely for (a) editorial use by press and/or industry analysts, (b) in connection with a normal, peer-reviewed, scientific publication, book or presentation, or the like. You may not alter or modify any image, in whole or in part, for any reason. You may not use any image in a manner that misrepresents the associated Pacific Biosciences product, service or technology or any associated characteristics, data, or properties thereof. You also may not use any image in a manner that denotes some representation or warranty (express, implied or statutory) from Pacific Biosciences of the product, service or technology. The rights granted by this Agreement are personal to you and are not transferable by you to another party.

You, and not Pacific Biosciences, are responsible for your use of the images. You acknowledge and agree that any misuse of the images or breach of this Agreement will cause Pacific Biosciences irreparable harm. Pacific Biosciences is either an owner or licensee of the image, and not an agent for the owner. You agree to give Pacific Biosciences a credit line as follows: "Courtesy of Pacific Biosciences of California, Inc., Menlo Park, CA, USA" and also include any other credits or acknowledgments noted by Pacific Biosciences. You must include any copyright notice originally included with the images on all copies.

IMAGES ARE PROVIDED BY Pacific Biosciences ON AN "AS-IS" BASIS. Pacific Biosciences DISCLAIMS ALL REPRESENTATIONS AND WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, OWNERSHIP, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL Pacific Biosciences BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES OF ANY KIND WHATSOEVER WITH RESPECT TO THE IMAGES.

You agree that Pacific Biosciences may terminate your access to and use of the images located on the PacificBiosciences.com website at any time and without prior notice, if it considers you to have violated any of the terms of this Image Use Agreement. You agree to indemnify, defend and hold harmless Pacific Biosciences, its officers, directors, employees, agents, licensors, suppliers and any third party information providers to the Site from and against all losses, expenses, damages and costs, including reasonable attorneys' fees, resulting from any violation by you of the terms of this Image Use Agreement or Pacific Biosciences' termination of your access to or use of the Site. Termination will not affect Pacific Biosciences' rights or your obligations which accrued before the termination.

I have read and understand, and agree to, the Image Usage Agreement.

I disagree and would like to return to the Pacific Biosciences home page.

Pacific Biosciences
Contact:

Breast Cancer Research Legend Mary-Claire King Identifies New Pathogenic Mutation with HiFi Sequencing

Thursday, October 29, 2020

Mary-Claire King

It’s Breast Cancer Awareness Month, and we can’t think of a better way to celebrate than to honor the passionate scientist who has perhaps single-handedly done more to advance breast cancer research than anyone else alive: Mary-Claire King, discoverer of the BRCA1 and BRCA2 genes. In recognition of her lifelong contributions, King was just awarded the prestigious William Allen Award, the top prize presented annually by the American Society of Human Genetics to recognize substantial and far-reaching scientific contributions to human genetics, carried out over a sustained period of scientific inquiry and productivity.

In a recent publication in the Journal of Medical Genetics, King and her collaborators at the University of Washington combined CRISPR-Cas9 targeting with HiFi sequencing to reveal novel and biologically relevant mutations in the BRCA1 gene.

The effort was driven by a need to better characterize the well-known BRCA1 and BRCA2 genes in families with hereditary breast cancer. Short-read sequencing “is of limited use for identifying complex insertions and deletions and other structural rearrangements,” the scientists note. “The BRCA1 genomic region is particularly challenging for short-read sequencing. It is composed of 42% Alu repeats, the second highest proportion in the genome, and a 30 kb tandem segmental duplication spanning its promoter and first two exons.” To expand the clinical utility of information about these genes in the future, much research remains to be done to characterize the many variants missed by short reads.

For this study, scientists aimed to sequence the BRCA1 and BRCA2 genes from individuals representing 19 families with a history of early-onset breast cancer. All of these individuals had previously had these genes analyzed with gene panels and whole exome sequencing, but no pathogenic mutations were found that explained the early onset breast cancer susceptibility.

To target the two genes of interest, the team used the HLS-CATCH CRISPR-based targeting method from Sage Science, extracting 200 kb of high molecular weight libraries ideal for use with PacBio sequencing. HiFi sequencing was performed on the Sequel System, with average genomic fragment length of about 10,000 bases to fully cover the two BRCA loci, including non-coding elements.

In one case, this approach unlocked a novel variant to explain the family’s history of cancer. “We identified an intronic SINE-VNTR-Alu retrotransposon insertion that led to the creation of a pseudoexon in the BRCA1 message and introduced a premature truncation,” the scientists report. The retrotransposon was nearly 3 kb long. “Multiple long reads included all elements of the mutation and of wild-type flanking BRCA1 intronic sequence, so that the mutation’s position and the sequence were clear,” the authors note, adding that the variant segregated with breast cancer throughout the family. After identifying this tough-to-find type of variant, the authors confirmed that the intronic repeat element can affect the final BRCA1 message by sequencing cDNAs from matching patient cells.

Based on these findings, the team suggests that there may be many other pathogenic complex structural variants. “It is possible, even likely, that complex mutations are common at tumour suppressor genes,” they write. “We suggest that complex mutations have thus far been rarely encountered, because they are difficult to detect with existing approaches.”

King and her collaborators believe the approach they used will be important for continuing to uncover these variants. “The genomic approach described here, integrating CRISPR–Cas9 excision of critical loci with long-read sequencing, yields complete sequence of targeted loci and thus can detect all classes of complex non-coding structural variants,” they report. “This combination of CRISPR–Cas9 excision and long-read sequencing reveals a class of complex, damaging and otherwise cryptic mutations that may be particularly frequent in  r suppressor genes replete with intronic repeats.”

 

Listen to King share the emotional and humorous story of the events leading to the funding of the project that resulted in the discovery of the BRCA1 gene – a true testament to her persistence and the constant challenge of balancing career and family, with a cameo from Joe DiMaggio!

Subscribe for blog updates:

Archives