Richard B. Hallick. Professor, Departments of Biochemistry and Molecular & Cellular Biology. Ph.D., University of Arizona. Plant molecular biology; organization and expression of chloroplast genes; RNA processing.

We are interested in problems in plant molecular biology, with special emphasis on RNA processing in the chloroplast. In recent years, work has been directed at the following aspects of chloroplast gene expression: (1) Determination of the structure and identity of chloroplast genes, and the arrangement of these genes into transcription units; (2) Studies on the temporal regulation of chloroplast gene expression during chloroplast biogenesis; (3) Analysis of enzymes involved in specific transcription of chloroplast genes in vitro and in processing of primary transcripts; (4) Studies on chloroplast RNA splicing.

Most chloroplast genes are organized into multicistronic transcription units. Many of the protein genes contain multiple introns that have highly conserved boundary sequences related to plant nuclear and chloroplast intron containing species. Current efforts are focused on the identification of chloroplast promoters via site specific mutagenesis, the determination of RNA processing steps required for RNA maturation, the development of techniques for studying chloroplast RNA splicing reactions, and analysis of the evolutionary origin of chloroplast introns and twintrons.

L. Hong and R.B. Hallick (1994) Gene structure and expression of a novel Euglena gracilis chloroplast operon encoding cytochrome b6 and the and e subunits of the H+-ATP synthase complex. Current Genetics 25:270-281.

J.K. Stevenson and R.B. Hallick (1994) The psaA operon pre-mRNA of the Euglena gracilis chloroplasts is processed into photosystem I and II mRNAs that accumulate differentially depending on the conditions of cell growth. The Plant Journal 5(2):247-260.

D.W. Copertino, E.T. Hall, F.W. VanHook, K.P. Jenkins, and R.B. Hallick (1994) A group III twintron encoding a maturase-like gene excises through lariat intermediates. Nucl. Acids Res. 22(6):1029-1036.

L. Hong and R.B. Hallick (1994) A Group III Intron is formed from Domains of Two Individual Group II Introns. Genes and Development 8:1589-1599.

L. Hong, J.K. Stevenson, W. Barry Roth, and R.B. Hallick (1995) Euglena gracilis chloroplast psbB, psbT, psbH and psbN: gene cluster regulation of psbB-psbT pre-mRNA processing. Mol. Gen. Genet. 247(2): 180-188.

M.D. Thompson, D.W. Copertino, E.Thompson, M.R. Favreau, and R.B. Hallick (1995) Evidence for the late origin of Introns in photosynthetic genes from an evoluationary analysis of genus Euglena. Nucl. Acids Res. 23(23): 4745-4752.

K.P. Jenkins, L. Hong, and R.B. Hallick (1995) Alternative splicing of the Euglena gracilis chloroplast roaA transcript. RNA 1:624-633.

Zhang, L., Jenkins, K.P., Stutz, E., and R.B. Hallick (1996) The Euglena gracilis intron-encoded mat2 locus in interrupted by three additional group II introns. RNA 1:1079-1088.

Thompson, MD, Zhang, L., Ling Hong, L., and Hallick, R.B. (1996) Two New group II twintrons in the Euglena gracilis chloroplast are absent in basally branching Euglena Species. Current Genetics 31(1): 89-95.

WB Roth, MD Thompson, and RB Hallick (1997). DNA Fingerprinting in a high school research-based science course. The American Biology Teacher 59(1):48-51.

NA Doetsch, MD Thompson, and RB Hallick (1997). A maturase-encoding group III twintron is conserved in deeply rooted Euglenoid species: Are group III introns the chicken or the egg?. Molecular Biology and Evolution, in Press.

MD Thompson, L Zhang, L Hong, and RB Hallick (1997). Extensive structural conservation exists among several homologs of two Euglena chloroplast group II introns. Molecular and General Genetics, in Press.