An mRNA that specifically accumulates in maize roots delineates a novel subset of developing cortical cells

Abstract

A near full-length cDNA clone (pZRP3) corresponding to an mRNA that accumulates specifically in roots of maize was isolated. The ZRP3 mRNA is ca. 600 nucleotides in length. The amino acid sequence of the predicted polypeptide is rich in leucine (16%), proline (11%), and cysteine (8.5%). The zrp3 gene appears to be expressed exclusively in roots, whereas other ZRP3-related genes are expressed in additional organs of the maize plant. In situ hybridization shows that ZRP3 mRNA accumulation is largely confined to the cells of the cortical ground meristem. Furthermore, accumulation of this mRNA occurs within a distinct subset of cortical cells, the inner three to four cell layers.

Biochemical and Molecular Biological Characterization of CAC2, the Arabidopsis thaliana Gene Coding for the Biotin Carboxylase Subunit of the Plastidic Acetyl-Coenzyme A Carboxylase

“…In situ hybridization to RNA using paraffin-embedded sections was conducted as described previously (John et al, 1992;Ke et al, 1997). 35S-Labeled RNA probes (sense and antisense) were synthesized from a subclone consisting of the 3'-most 600 nucleotides of the CAC2 cDNA.…”

Root-preferential mRNA accumulation in Zea mays

“…Northern blot analysis suggests that an mRNA encoding a caffeic acid 0-methyltransferase (COMT) involved in lignin biosynthesis accumulates preferentially in com roots (Collazo et al, 1992). An mRNA (ZRP3) in com that encodes a protein whose function is unknown accumulates largely in the cortical ground meristem of the root (John et al, 1992). A homolog (AX92) from Brassica napus accumulated in a similar fashion (Dietrich et al, 1989), and another homolog (DC2.15) in carrot was expressed during somatic embryogenesis (Aleith and Richter, 1990).…”

“…To begin the investigation of the molecular mechanisms of root development and function, we isolated three cDNA clones that corresponded to mRNAs that accumulated preferentially in the roots of maize (John, 1991;John et al, 1992). This report documents the characterization of one of these cDNA clones, and an analysis of the transcriptional control for another.…”

“…The study of the regulation of tissue-and cell-type preferential mRNA accumulation is a means to elucidate the genetic and molecular basis of plant development and function. Because of the important function and unique developmental characteristics of the root, recent investigations have focused on differential gene expression in this organ (Evans et al, 1988;Keller and Lamb, 1989;Montoliu et al, 1989;Conkling et al, 1990;Lemer and Raikhel, 1990;Mclean et al, 1990;Schiefelbein and Benfey, 1991;Yamamoto et al, 1991;CoUazo et al, 1992;Dietrich, et al, 1992;John et al, 1992).…”

Histological Observation of Red Pigment Formed on Shoot Stem of Lithospermum erythrorhizon.

“…LEDI-2 cDNA, whose expression was specifically observed in the dark, was cloned from cell cultures by a subtractive hybridization technique . The deduced polypeptide sequence shares a significant homology to the known plant proteins specifically expressed in the root, such as ZRP3, RCc2, PVR5 (John et al, 1992, Xu et al, 1995, Choi et al, 1996, but the biological roles of those polypeptides have so far been unknown. Northern blot hybridization and recent functional analyses of LEDI-2 indicated that the gene product of LEDI-2 has a close correlation with the production of shikonin in the cell cultures .…”