Robert Franks

Assistant Professor of Genetics

PhD, University of California, Los Angeles
Postdoctoral, University of Maryland, College Park
Postdoctoral, University of California, Berkeley

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Development of the Carpel Margin Meristem
in Arabidopsis thaliana

Dr. Robert Franks studies how organ size and shape are controlled in the flowering plant Arabidopsis thaliana. Reproductive competence of flowering plants requires proper development of the carpel, which is the female reproductive organ of the plant. The meristematic regions along the margin of the developing carpel generate ovules that will later develop into seeds. These meristematic regions are functionally analogous to the mammalian ovary and placenta.

A confocal microscopy image of a developing Arabidopsis gynoecium shows two rows of interdigitated ovule primordia arising from the carpel margin meristem. Once fertilized these ovule primordia will develop into seeds. Proper development of the carpel margin meristem is thus critical for female reproductive competence and for agricultural productivity in many agricultural varieties.

The carpel margin meristems (CMMs) provide an excellent system to study basic problems in developmental biology such as patterning, the regulation of cellular proliferation and the control of organ size and shape. Dr. Franks' research program seeks to clarify basic mechanisms of organ size and shape regulation and understand relationships between patterning cues and cellular proliferation within the carpel. Current research focuses on (1) characterization of expression patterns of key regulatory molecules and patterns of cellular division during carpel development and (2) identification and functional studies of additional genes that play a critical role in CMM development.

A scanning electron microscopy image of a mutant Arabidopsis flower. Loss-of-function mutations in two genes, SEUSS and LEUNIG, alter petal shape. Resulting petals are filamentous or club-shaped instead of blade-shaped. Our lab works to elucidate molecular genetic factors that control organ shape and size. See Development 129: 253-263.

For more information, e-mail Dr. Robert Franks.

This work is supported by a grant from the National Science Foundation to Robert Franks. For more information, see NSF award #0416759:

Selected Publications:

Franks, R.G., Liu, Z., and Fischer, R.L. (2006) SEUSS and LEUNIG regulate cell proliferation, vascular development and organ polarity in Arabidopsis petals. Planta 224: 801–811.

Bao, X., Franks, R.G., Levin, J.Z., and Liu, Z. 2004. Repression of AGAMOUS by BELLRINGER in floral and inflorescence meristems. The Plant Cell 16: 1478-1489. [pdf file]

Franks, R.G., Wang, C., Levin, J.Z., and Liu, Z. 2002. SEUSS, a member of a novel family of plant regulatory proteins, represses floral homeotic gene expression with LEUNIG. Development 129: 253-263. [pdf file]

Franks, R.G., and Liu, Z. 2001. Floral homeotic gene regulation. Horticultural Reviews 27: 41-77.

Liu, Z., Franks, R.G., and Klink, V.P. 2000. Regulation of gynoecium marginal tissue formation by LEUNIG and AINTEGUMENTA. Plant Cell 12: 1879-1892.

Wharton, K.A., Jr., Franks, R.G., Kasai, Y., and Crews, S.T. 1994. Control of CNS midline transcription by asymmetric E-box-like elements: similarity to xenobiotic responsive regulation. Development 120: 3563-3569.

Franks, R.G., and Crews, S.T. 1994. Transcriptional activation domains of the single-minded bHLH protein are required for CNS midline cell development. Mech Dev. 45: 269-77.

Crews, S.T., Franks, R.G., Hu, S., Matthews, B., and Nambu, J.R. 1992. The Drosophila single-minded gene and the molecular genetics of CNS midline development. J. Exp. Zool. 261: 234-244.

Nambu, J.R., Franks, R.G., Hu, S., and Crews, S.T. 1990. The single-minded gene of Drosophila is required for the expression of genes important for the development of CNS midline cells. Cell 63: 63-75.

For more information contact:

Dr. Robert Franks
Department of Genetics
North Carolina State University
Raleigh, NC 27695-7614
Phone: (919) 513-7705
E-mail

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