- PROFESSOR Medicine, Liver Diseases
- ASSOCIATE PROFESSOR Surgery
B.S., The University of Michigan
M.S., The University of California
Ph.D., The Rockefeller University
The Rockefeller University
Laboratory of Genetics
The Rockefeller University
Laboratory of Biology of Addictive Diseases
1976 - 1981
Rockefeller University Graduate Fellowship
Steinhaus Memorial Teaching Award
1973 - 1975
Public Health Service Traineeship
Anti-Viral Treatments Following Liver Transplantation
Branch A, Robertson HD. A replication cycle for viroids and other small infectious RNA's. Science 1984; 223: 450-455.
Branch A, Benenfeld BJ, Baroudy BM, Wells FV, Gerin JL, Robertson HD. An ultraviolet-sensitive RNA structural element in a viroid-like domain of the hepatitis delta virus. Science 1986; 243: 649-652.
Branch A, Robertson HD. Efficient trans cleavage and a common structural motif for the ribozymes of the human hepatitis delta agent. Natl. Acad. Sci., U. S. A. 1991; 88: 10163-10167.
Branch A, Polaskova JA, Schreiber DR. Tm studies of a tertiary structure from the human hepatitis delta agent which functions in vitro as a ribozyme control element. Nucleic Acids Res 1995 Nov; 23(21): 4391-4399.Viroids and other circular subviral RNA pathogens, such as the hepatitis delta agent, use a rolling circle replication cycle requiring an intact circular RNA. However, many infectious RNAs have the potential to form self-cleavage structures, whose formation must be controlled in order to preserve the circular replication template. The native structure of delta RNA contains a highly conserved element of local tertiary structure which is composed of sequences partially overlapping those needed to form the self-cleavage motif. A bimolecular complex containing the tertiary structure can be made. We show that when it is part of this bimolecular complex the potential cleavage site is protected and is not cleaved by the delta ribozyme, demonstrating that the element of local tertiary structure can function as a ribozyme control element in vitro. Physical studies of the complex containing this element were carried out. The complex binds magnesium ions and is not readily dissociated by EDTA under the conditions tested; > 50% of the complexes remain following incubation in 1 mM EDTA at 60 degrees C for 81 min. The thermal stability of the complex is reduced in the presence of sodium ions. A DNA complex and a perfect RNA duplex studied in parallel showed a similar effect, but of lesser magnitude. The RNA complex melts at temperatures approximately 10 degrees C lower in buffers containing 0.5 mM MgCl2 and 100 mM NaCl than in buffers containing 0.5 mM MgCl2 with no NaCl (78.1 compared with 87.7 degrees C). The element of local tertiary structure in delta genomic RNA appears to be a molecular clamp whose stability is highly sensitive to ion concentration in the physiological range.
Branch A. A Good Antisense Molecule Is Hard to Find. Trends in Biochemical Sciences 1998; 23: 45-50.
Branch A. Hepatitis C Virus Codes for Proteins and Replicates: Does It also Trigger the Interferon Response?. Seminars in Liver Disease 2000; 20: 57-68.
Physicians and scientists on the faculty of the Icahn School of Medicine at Mount Sinai often interact with pharmaceutical, device and biotechnology companies to improve patient care, develop new therapies and achieve scientific breakthroughs. In order to promote an ethical and transparent environment for conducting research, providing clinical care and teaching, Mount Sinai requires that salaried faculty inform the School of their relationships with such companies.
Below are financial relationships with industry reported by Dr. Branch during 2012 and/or 2013. Please note that this information may differ from information posted on corporate sites due to timing or classification differences.
- Gilead Sciences, Inc.; Janssen Scientific Affairs, LLC
Mount Sinai's faculty policies relating to faculty collaboration with industry are posted on our website at http://icahn.mssm.edu/about-us/services-and-resources/faculty-resources/handbooks-and-policies/faculty-handbook. Patients may wish to ask their physician about the activities they perform for companies.
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