Barbara B. Knowles, Ph.D.

Barbara B. Knowles, Ph.D., was an investigator at The Wistar Institute from 1967 to 1993. Today, Knowles is Vice President for Training and External Collaborations at The Jackson Laboratory, where she is also a Senior Staff Scientist. She is a Presidential Professor at the University of Maine where she serves as co-director of the Institute for Molecular Biophysics.

In 1978, Knowles co-discovered an antibody to SSEA-1 (Stage-Specific Embryonic Antigen 1) with Wistar colleague Davor Solter, M.D., Ph.D.(http://www.wistar.org/research_facilities/solter.htm). This antibody has an affinity for mouse embryonic stem cells, as well as for certain other mouse stem and cancer cells and it also reacts with human neutrophils, a type of white blood cell that travels through the body to sites of infection. The antibody to SSEA-1 was later incorporated into an imaging agent called NeutroSpec™, which was approved in 2004 by the Food and Drug Administration for detecting appendicitis and is under investigation for use in diagnosing other hidden infections. Their antibodies to SSEA-3 and -4 serve to mark human embryonic stem cells.

Today, Knowles explores the genetic control and molecular mechanisms at play during the oocyte-to-embryo transition. In a recent advance, she and her research group discovered that the maternal transcriptome in mouse eggs and very early embryos contains unusually high levels of transposable elements (TEs). TEs, also known as jumping genes and sometimes referred to as “junk DNA,” are discrete DNA segments that are excised from one site in the genome and then reintegrated into another site, in effect moving genetic information and remodeling the genome. These findings suggest that TEs may actually participate in governing the transition from oocyte to embryo.