The Arabidopsis Transcription FactorLUH/MUM1Is Required for Extrusion of Seed Coat Mucilage

Jun Huang,Nicholas C Carpita,Elahe Esfandiari,George W Haughn,Danisha Debowles,Gillian Dean

doi:10.1104/pp.111.172023

Abstract

During differentiation, the Arabidopsis (Arabidopsis thaliana) seed coat epidermal cells secrete mucilage composed primarily of rhamnogalacturonan I that is extruded from the seed coat upon imbibition. The mucilage of the mucilage modified1 (mum1) mutant contains rhamnogalacturonan I that is more highly branched and lacks the ability to be extruded when exposed to water. Our cloning of the MUM1 gene shows that it encodes a putative transcription factor, LEUNIG_HOMOLOG (LUH). Cellular localization and transcriptional assay results suggest that LUH/MUM1 is a nucleus-localized transcriptional activator. LUH/MUM1 is expressed in all the tissues examined, including the seed coat. Quantitative reverse transcription-polymerase chain reaction data suggest that LUH/MUM1 is expressed throughout seed coat development, reaching peak expression late in differentiation. LUH1/MUM1 expression in plants homozygous for mutations in several genes encoding regulators of seed coat mucilage was unchanged. Thus, LUH/MUM1 expression appears to be independent of other transcription factors known to regulate aspects of seed coat mucilage biology. The expression in the luh/mum1 mutant of three genes encoding enzymes needed for mucilage extrusion, MUM2, SUBSILIN PROTEASE1.7, and β-XYLOSIDASE1, was reduced relative to that of the wild type. Overexpression of MUM2 could partially rescue the mum1 phenotype. These data suggest that LUH/MUM1 is a positive regulator of all three genes.

Highlights

Benzathine penicillin G and procaine penicillin G are the antimicrobial agents most commonly used to treat syphilis
A parallel case was reported by Green et al, whose patient developed atypical basal meningitis one year after treatment with intramuscular benzathine penicillin 6-48 g for latent syphilis.[5] (Paresis of the oculomotor nerve developed and the cerebrospinal fluid (CSF) showed an increased cell count and protein concentration and a positive Venereal Disease Research Laboratory (VDRL) test
In a recent review of neurosyphilis, Stockli emphasised that the common treatment regimens with benzathine penicillin and procaine penicillin do not ensure a treponemicidal concentration of penicillin in the CSF.[2]

Summary

Neurosyphilis after treatment of latent syphilis with benzathine penicillin

J0RGEN J0RGENSEN, GYRD TIKJ0B, AND KAARE WEISMANN From the Department of Dermatology and Venereology, Bispebjerg Hospital, Copenhagen, Denmark. SUMMARY Two patients developed neurosyphilis after treatment of latent syphilis with intramuscular benzathine penicillin. The cases confirm recent investigations that show that neither benzathine penicillin nor procaine penicillin in the standard doses results in treponemicidal concentrations of penicillin in cerebrospinal fluid. Neurosyphilis can be treated effectively by intravenous benzylpenicillin infusions of 18 to 216 g daily for 15 days

Introduction

Case reports

Discussion