A Career in Patent Law: At the Cutting Edge of Science, but Not at the Bench.

Patent law is an area that many people move into after obtaining a PhD in biomedical science. Close to the cutting edge of research, patent agents draft detailed descriptions of new biotechnology inventions required for patent applications and engage with patent offices during the review process known as patent prosecution. Jobs are also available as patent examiners who examine these patent applications, and it is common for individuals to move between the two jobs.

Differential regulation of the activity of the 42 kD mitogen activated protein kinase (p42mapk) during enterocyte differentiation in vivo.

The family of mitogen activated protein (MAP) kinases appear to play a central role in relaying signals generated by receptor protein tyrosine kinases (RPTK) from the cell surface to the nucleus. We previously demonstrated that undifferentiated and mitotically active crypt cells have high levels of tyrosine phosphorylated proteins (DR Burgess, W Jiang, S Mamajiwalla and W Kinsey. 1989.

Intestinal crypt cells contain higher levels of cytoskeletal-associated pp60c-src protein tyrosine kinase activity than do differentiated enterocytes.

Undifferentiated crypt cells from chicken small intestine contain 15-fold higher levels of tyrosine-phosphorylated proteins than do differentiated enterocytes located at the villus apex. The tyrosine kinase activity and the tyrosine-phosphorylated proteins are associated with the Triton-insoluble cytoskeleton. To determine whether: (1) pp60c-src is an active tyrosine kinase in crypt cell cytoskeletons and (2) cytoskeletal-associated pp60c-src activity decreases as crypt cells differentiate, we isolated pp60c-src from subcellular fractions of cells along the crypt-villus axis of chicken small intestine and measured its protein kinase activity.

The cytoskeleton in development of epithelial cell polarity.

The polarization of intestinal epithelial cells and the stereotypic arrangement of their actin-based cytoskeleton have made these epithelia an excellent system to explore the organization and formation of a cortical actin-based cytoskeleton. Through a combined morphological and biochemical analysis, the molecular arrangement of many of the components of the brush border has been elucidated. Study of brush border assembly in the Crypts of Lieberkühn suggests that cytoskeletal mRNA and protein expression, as well as morphological development, occur rapidly following cell differentiation.