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Reid Johnson, Ph.D.

Affiliations

Professor, Biological Chemistry

Member, Molecular Biology Institute, JCCC Gene Regulation Program Area, ACCESS Program: Dept. of Biological Chemistry

Education:
Certification Type:	Award, American Cancer Society Faculty Research Award Professional Affiliation, Basil O'Connor Starter Scholar Award: March of Dimes Birth Defects Foundation Professional Affiliation, Fellow, American Academy of Microbiology Professional Affiliation, Member of the Genetics Training Grant Committee Professional Affiliation, Member of the Molecular Biology Institute Council Award, NIH MERIT Award Award, Searle Scholar - The Chicago Community Trust
Degree:	Ph.D.,

Contact Information:

Work Email Address:	rcjohnson@mednet.ucla.edu

Laboratory Address:	Laboratory Department of Biological Chemistry David Geffen School of Medicine at UCLA BSRB 357A Los Angeles, CA 90095 UNITED STATES
Work Address:	Office Department of Biological Chemistry David Geffen School of Medicine at UCLA BSRB 351B Los Angeles, CA 90095 UNITED STATES
Work Address:	351B BSRB CAMPUS - 173717 CA UNITED STATES

Direct Contact Information:

Work Phone Number:	(310) 825-7800

Research Interest:

Gene expression and chromosome biology in bacteria and yeast

Reid Johnson, a professor in the Biological Chemistry Department, studies chromosome structure and function in microorganisms. Dr. Johnson has had a long term interest in specialized DNA recombination reactions, especially site-specific DNA recombination reactions. In 1985, he developed an in vitro system for dissecting a DNA inversion reaction that regulates flagellin biosynthesis in Salmonella. This recombination reaction enables the microbial pathogen to escape a host immune response by changing the antigenic character of its major surface protein. Mechanistic investigations into the Salmonella DNA inversion reaction led to the discovery of recombinational enhancer elements and a global regulatory protein Fis that mediates enhancer activity. The Johnson lab recently demonstrated that DNA exchange is mediated by a translocation of recombinase subunits that are covalently-linked to the cleaved DNA ends within the synaptic complex and that the Fis/enhancer system controls the direction and processivity of this subunit rotation reaction. The subunit rotation mechanism is likely to operate for all members of the serine recombinase family but is unlike DNA exchange reactions in other recombination systems.

The Fis protein is one of a small group of abundant DNA bending proteins in bacteria that have diverse roles in regulating recombination, transcription, and replication reactions as well as in chromosome packaging. In addition to investigating the control of specific DNA transactions by nucleoid proteins, the Johnson lab is currently emphasizing their role in chromosome organization. The laboratory recently solved a series of X-ray structures of Fis bound to different curved DNA sequences and, together with biophysicist John Marko, discovered that Fis condenses chromosomes in vitro by stabilizing DNA loops. These activities imply that Fis may be a prominent factor responsible for establishing the looped-domain structure of the bacterial chromosome. Research on bacterial chromosome binding proteins has been extended to the abundant HMGB class of chromatin-associated proteins in eukaryotic cells. Earlier work elucidated the mode of DNA binding and bending, in part through an NMR-based structure of a DNA complex of an HMGB protein from the yeast S. cerevisiae in collaboration with Juli Feigon’s laboratory at UCLA. Current efforts are focused on the in vivo binding specificity and function of HMGB proteins in yeast.

Additional Information:

Reid C. Johnson is a Professor of Biological Chemistry in the UCLA School of Medicine, where he joined the faculty in 1986. He received his Ph.D. from the University of Wisconsin-Madison in 1983 and did postdoctoral work at Caltech. Dr. Johnson has had a long standing research interest in mechanisms and control of specialized DNA recombination reactions, such as transposition and site-specific recombination. An additional focus of his laboratory has concerned the varied functions of abundant nucleoid-associated DNA bending proteins in regulating transcription reactions and chromosome behavior in microorganisms. This work has recently been extended to include HMGB chromatin-associated proteins in eukaryotic cells, especially yeast.

Publications:

Dhar G, Heiss JK, and Johnson RC Mechanical constraints on Hin subunit rotation imposed by the Fis-enhancer system and DNA supercoiling during site-specific recombination. Molecular Cell . 2009; 34: 746-759.

Dhar G, McLean MM, Heiss JK, and Johnson RC The Hin recombinase assembles a tetrameric protein swivel that exchanges DNA strands. Nucleic Acids Res.. 2009; 37: 746-759.

Johnson RC, and Heiss JK Assembly of a tightly interwound DNA recombination complex poised for deletion. Structure. 2008; 16: 653-655.

Johnson RC, Stella S, Heiss JK Bending and compaction of DNA by proteins. In: Protein-Nucleic Acid Interactions, eds: PA Rice and CC Correll (RSC Press, Cambridge, UK) 2008; pp. 176-220.

Papagiannis CV, Sam MD, Abbani MA, Cascio D, Clubb, RT, and Johnson, RC Fis targets assembly of the Xis nucleoprotein filament to promote excisive recombination by phage lambda. J. Mol. Biol.. 2007; 367: 328-343.

Abbani MA, Papagiannis CV, Sam MD, Cascio D, Johnson RC and Clubb RT Structure of the cooperative Xis-DNA complex reveals a micronucleoprotein filament that regulates phage lambda intasome assembly. Proc. Natl. Acad. Sci. USA. 2007; 104: 2109-2114.

Typas A, Stella S, Johnson RC, and Hengge R The -35 sequence and the Fis-sigma factor interface determine sigma S selectivity of the proP (P2) promoter in Escherichia coli. Mol. Microbiol.. 2007; 63: 780-796.

Hanover, J.A. Love, D.C. DeAngelis, N. O'Kane, M.E. Lima-Miranda, R. Schulz, T. Yen, Y-M. Johnson, R.C. Prinz, W.A. The high mobility group box transcription factor NHP6Ap enters the nucleus by a calmodulin-dependent, Ran-independent pathway. J. Biol. Chem.. 2007; 282: 33,742-33,751.

Skoko D, Yoo D, Bai H, Schnurr B, Yan J, McLeod SM, Marko JF, and Johnson RC Mechanism of chromosome compaction and looping by the Escherichia coli nucleoid protein Fis. J. Mol. Biol.. 2006; 364: 777-798.

Dai Y, Wong B, Yen YM, Oettinger MA, Kwon J, and Johnson RC Determinants of HMGB proteins required to promote RAG1/2-recombination signal sequence complex assembly and catalysis during V(D)J recombination.. Molecular and Cellular Biology. . 2005; 25(11): 4413-4425.

Skoko D, Yan J, Johnson RC, and Marko JF Low-force DNA condensation and discontinuous high-force decondensation reveal a loop-stabilizing function of the protein Fis. Phys. Rev. Lett.. 2005; 95: 208101.

Dhar G, Sanders ER, and Johnson RC Architecture of the Hin synaptic complex during recombination: the recombinase subunits translocate with the DNA strands.. Cell. . 2004; 119: 33-45.

Sam MD, Cascio D, Johnson RC, and Clubb RT Crystal structure of the excisionase-DNA complex from bacteriophage lambda.. Journal of Molecular Biology. . 2004; 338: 229-240.

Skoko D, Wong B, Johnson RC, and Marko JF Micromechanical analysis of the binding of DNA-bending proteins HMGB1, NHP6A, and HU reveals their ability to form highly stable DNA-protein complexes.. Biochemistry. . 2004; 43: 13867-13874.

Sanders ER and Johnson RC Stepwise dissection of the Hin-catalyzed recombination reaction from synapsis to resolution.. Journal of Molecular Biology. . 2004; 340: 753-766.

Merickel SK and Johnson RC Topological analysis of Hin-catalyzed DNA recombination in vivo and in vitro.. Mol. Microbiol.. 2004; 51: 1143-1154.

Aiyar SE, McLeod SM, Ross W, Hirvonen CA, Thomas MS, Johnson RC, and Gourse RL Architecture of Fis-activated transcription complexes at the Escherichia coli rrnB P1 and rrnE P1 promoters.. Journal of Molecular Biology. . 2002; 316: 501-516.

Wong B, Masse JE, Yen Y-M, Feigon J and Johnson RC Binding to cisplatin-modified DNA by the S. cerevisiae HMGB protein NHP6A.. Biochemistry. 2002; 41: 5404-5414.

Sam MD, Papagiannis CV, Connolly KM, Corselli L, Iwahara J, Lee J, Phillips M, Wojciak JM, Johnson RC, and Clubb RT Regulation of directionality in bacteriophage lambda site-specific recombination: structure of the Xis protein.. Journal of Molecular Biology. 2002; 324: 791-805.

Merickel SK, Sanders ER, Vzquez-Ibar JL, and Johnson RC Subunit exchange and the role of dimer flexibility in DNA binding by the Fis protein.. Biochemistry . 2002; 41: 5788-5798.

Chiu TK, Sohn C, Dickerson RE, and Johnson RC Testing water-mediated DNA recognition by the Hin recombinase.. EMBO J.. 2002; 21: 801-814.

McLeod SM, Aiyar SE, Gourse RL & Johnson RC The C-terminal domains of the RNA polymerase alpha subunits: Contact site with Fis and localization during co-activation with CRP at the Escherichia coli proP P2 promoter.. J. Mol. Biol. . 2002; 316: 517-529.

Mitsouras K, Wong B, Arayata C, Johnson RC, and Carey M The DNA architectural protein HMGB1 displays two distinct modes of action that promote enhanceosome assembly.. Molecular and Cellular Biology. . 2002; 22: 4390-4401.

Masse JE, Wong B, Yen Y-M, Allain FHT, Johnson RC and Feigon J The S. cerevisiae DNA architectural HMGB protein NHP6A complexed with DNA: DNA and protein conformational changes upon binding.. J. Mol. Biol. . 2002; 323: 263-284.

McLeod SM and Johnson RC Control of transcription by nucleoid-associated proteins.. Current Opinion in Microbiology. 2001; 4: 152-159.

Yen YM, Roberts PM and Johnson RC Nuclear localization of the S. cerevisiae HMG protein NHP6A occurs by a Ran-independent non-classical pathway.. Traffic. 2001; 2: 449-464.

McLeod SM, Xu J and Johnson RC Co-activation of the RpoS-dependent proP P2 promoter by Fis and CRP.. J. Bacteriol.. 2000; 182: 4180-4187.

Ellwood KB, Yen YM, Johnson RC, and Carey M Mechanism for specificity by HMG-1 in enhanceosome assembly.. Molecular and Cellular Biology. . 2000; 20: 4359-4370.

Cheng YS, Yang WZ, Johnson RC, and Yuan HS Structural analysis of the transcriptional activation on Fis: crystal structures of six Fis mutants with different activation properties.. Journal of Molecular Biology. . 2000; 302: 1139-1151.

McLeod SM, Xu J, Crampton SE, Gaal T, Gourse RL and Johnson RC Localization of amino acids required for Fis to function as a class II transcriptional activator at the RpoS-dependent proP P2 promoter.. J. Mol. Biol.. 1999; 294: 333-346.

Ellwood K, Huang W, Johnson RC and Carey M Multiple layers of cooperativity regulate enhancesome-responsive RNA polymerase II transcription complex assembly.. Mol. Cell. Biol.. 1999; 19: 2613-2623.

Allain FH, Yen YM, Masse JE, Schultze P, Dieckmann T, Johnson RC, Feigon J Solution structure of the HMG protein NHP6A and its interaction with DNA reveals the structural determinants for non-sequence-specific binding.. The EMBO J. . 1999; 18: 2563-2579.

Landis L, Xu J, and Johnson RC, The cAMP receptor protein CRP can function as an osmoregulator of transcription in Escherichia coli.. Genes & Development. . 1999; 13: 3081-3091.

Merickel SK, Haykinson MJ, and Johnson RC Communication between Hin recombinase and Fis regulatory subunits during coordinate activation of Hin-catalyzed site-specific DNA inversion.. Genes & Development . 1998; 12: 2803-2816.

Yang WZ, Ko TP, Corselli L, Johnson RC and Yuan HS Conversion of a beta-strand to an alpha-helix induced by a single-site mutation identified in the crystal structure of Fis mutant Pro26Ala.. Protein Science 1998; 7: 1875-1883.

Yen YM, Wong B, and Johnson RC Determinants of DNA binding and bending by the Saccharomyces cerevisiae high mobility group protein NHP6A that are important for its biological activities. Role of the unique N terminus and putative intercalating methionine.. The Journal of Biological Chemistry. . 1998; 273: 4424-4435.

Xu J and Johnson RC Activation of RpoS-dependent proP P2 transcription by the Fis protein in vitro.. Journal of Molecular Biology. . 1997; 270: 346-359.

Safo MK, Yang WZ, Corselli L, Cramton SE, Yuan HS, and Johnson RC The transactivation region of the Fis protein that controls site-specific DNA inversion contains extended mobile beta-hairpin arms.. The EMBO J. . 1997; 16: 6860-6873.

Haykinson MJ, Johnson LM, Soong J, and Johnson RC The Hin dimer interface is critical for Fis-mediated activation of the catalytic steps of site-specific DNA inversion.. Current Biology . 1996; 6: 163-177.

Pan CQ, Finkel SE, Cramton SE, Feng JA, Sigman DS, and Johnson RC Variable structures of Fis-DNA complexes determined by flanking DNA-protein contacts.. Journal of Molecular Biology. . 1996; 264: 675-695.

Paull TT, Carey M and Johnson RC Yeast HMG proteins NHP6A/B potentiate promoter-specific transcriptional activation in vivo and assembly of pre-initiation complexes in vitro.. Genes and Development. 1996; 10: 2769-2781.


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