The Maize Regulatory Gene B-Peru Contains a DNA Rearrangement That Specifies Tissue-Specific Expression Through Both Positive and Negative Promoter Elements

Corresponding author: Vicki L. Chandler, Department of Plant Sciences, 303 Forbes Hall, University of Arizona, Tucson, AZ 85721, chandler{at}ag.arizona.edu (E-mail).

Communicating editor: J. CHORY

The B-Peru allele of the maize b regulatory gene is unusual relative to most b alleles in that it is expressed in the aleurone layer of the seed. It is also expressed in a subset of plant vegetative tissues. Transgenic maize plants containing the B-Peru gene with the first 710 bases of upstream sequence conferred the same levels of aleurone expression as nontransgenic B-Peru plants, but no pigment was made in vegetative tissues. Transient transformation assays in aleurone tissue localized the aleurone-specific promoter to the first 176 bases of the B-Peru upstream region and identified two critically important regions within this fragment. Mutation of either region alone reduced expression greater than fivefold. Surprisingly, the double mutation actually increased expression to twice the native promoter level. Our results suggest that these two critical sequences, which lie close together in the promoter, may form a negative regulatory element. Several lines of evidence suggest that the B-Peru promoter arose through the translocation of an existing aleurone-specific promoter to the b locus. Immediately upstream of the aleurone-specific promoter elements and in the opposite orientation to the b coding sequence is a pseudogene sequence with strong similarity to a known class of proteins. Our findings that novel aleurone-specific promoter sequences of the B-Peru transcription factor are found adjacent to part of another gene in a small insertion are quite unexpected and have interesting evolutionary implications.

This article has been cited by other articles:

				K. McGinnis, N. Murphy, A. R. Carlson, A. Akula, C. Akula, H. Basinger, M. Carlson, P. Hermanson, N. Kovacevic, M. A. McGill, et al. Assessing the Efficiency of RNA Interference for Maize Functional Genomics Plant Physiology, April 1, 2007; 143(4): 1441 - 1451. [Abstract] [Full Text] [PDF]

				F. Zhang and T. Peterson Gene Conversion Between Direct Noncoding Repeats Promotes Genetic and Phenotypic Diversity at a Regulatory Locus of Zea mays (L.) Genetics, October 1, 2006; 174(2): 753 - 762. [Abstract] [Full Text] [PDF]

				K. M. McGinnis, C. Springer, Y. Lin, C. C. Carey, and V. Chandler Transcriptionally Silenced Transgenes in Maize Are Activated by Three Mutations Defective in Paramutation Genetics, July 1, 2006; 173(3): 1637 - 1647. [Abstract] [Full Text] [PDF]

				M. Stam, C. Belele, W. Ramakrishna, J. E. Dorweiler, J. L. Bennetzen, and V. L. Chandler The Regulatory Regions Required for B' Paramutation and Expression Are Located Far Upstream of the Maize b1 Transcribed Sequences Genetics, October 1, 2002; 162(2): 917 - 930. [Abstract] [Full Text] [PDF]

				M. Stam, C. Belele, J. E. Dorweiler, and V. L. Chandler Differential chromatin structure within a tandem array 100 kb upstream of the maize b1 locus is associated with paramutation Genes & Dev., August 1, 2002; 16(15): 1906 - 1918. [Abstract] [Full Text] [PDF]

				D. A. Selinger and V. L. Chandler B-Bolivia, an Allele of the Maize b1 Gene with Variable Expression, Contains a High Copy Retrotransposon-Related Sequence Immediately Upstream Plant Physiology, March 1, 2001; 125(3): 1363 - 1379. [Abstract] [Full Text]

				P. Zhang, S. Chopra, and T. Peterson A Segmental Gene Duplication Generated Differentially Expressed myb-Homologous Genes in Maize PLANT CELL, December 1, 2000; 12(12): 2311 - 2322. [Abstract] [Full Text]

				S. M. Cocciolone, L. V. Sidorenko, S. Chopra, P. M. Dixon, and T. Peterson Hierarchical Patterns of Transgene Expression Indicate Involvement of Developmental Mechanisms in the Regulation of the Maize P1-rr Promoter Genetics, October 1, 2000; 156(2): 839 - 846. [Abstract] [Full Text]

				K. Petroni, E. Cominelli, G. Consonni, G. Gusmaroli, G. Gavazzi, and C. Tonelli The Developmental Expression of the Maize Regulatory Gene Hopi Determines Germination-Dependent Anthocyanin Accumulation Genetics, May 1, 2000; 155(1): 323 - 336. [Abstract] [Full Text]

				D. A. Selinger and V. L. Chandler Major recent and independent changes in levels and patterns of expression have occurred at the b gene, a regulatory locus in maize PNAS, December 21, 1999; 96(26): 15007 - 15012. [Abstract] [Full Text] [PDF]

				D. A. Selinger and V. L. Chandler A Mutation in the pale aleurone color1 Gene Identifies a Novel Regulator of the Maize Anthocyanin Pathway PLANT CELL, January 1, 1999; 11(1): 5 - 14. [Abstract] [Full Text]