Biomedical subjects

Dorothee U Kloos

Publications and source records attributed to Dorothee U Kloos.

4 recordsLinked to original sources

PubMed2006

Taproot promoters cause tissue specific gene expression within the storage root of sugar beet.

The storage root (taproot) of sugar beet (Beta vulgaris L.) originates from hypocotyl and primary root and contains many different tissues such as central xylem, primary and secondary cambium, secondary xylem and phloem, and parenchyma. It was the aim of this work to characterize the promoters of three taproot-expressed genes with respect to their tissue specificity. To investigate this, promoters for the genes Tlp, His1-r, and Mll were cloned from sugar beet, linked to reporter genes and transformed into sugar beet and tobacco. Reporter gene expression analysis in transgenic sugar beet plants revealed that all three promoters are active in the storage root. Expression in storage root tissues is either restricted to the vascular zone (Tlp, His1-r) or is observed in the whole organ (Mll). The Mll gene is highly organ specific throughout different developmental stages of the sugar beet. In tobacco, the Tlp and Mll promoters drive reporter gene expression preferentially in hypocotyl and roots. The properties of the Mll promoter may be advantageous for the modification of sucrose metabolism in storage roots.

Beta vulgaris↗

PubMed2004

A sugar beet chlorophyll a/b binding protein promoter void of G-box like elements confers strong and leaf specific reporter gene expression in transgenic sugar beet.

BACKGROUND: Modification of leaf traits in sugar beet requires a strong leaf specific promoter. With such a promoter, expression in taproots can be avoided which may otherwise take away available energy resources for sugar accumulation. RESULTS: Suppression Subtractive Hybridization (SSH) was utilized to generate an enriched and equalized cDNA library for leaf expressed genes from sugar beet. Fourteen cDNA fragments corresponding to thirteen different genes were isolated. Northern blot analysis indicates the desired tissue specificity of these genes. The promoters for two chlorophyll a/b binding protein genes (Bvcab11 and Bvcab12) were isolated, linked to reporter genes, and transformed into sugar beet using promoter reporter gene fusions. Transient and transgenic analysis indicate that both promoters direct leaf specific gene expression. A bioinformatic analysis revealed that the Bvcab11 promoter is void of G-box like regulatory elements with a palindromic ACGT core sequence. The data indicate that the presence of a G-box element is not a prerequisite for leaf specific and light induced gene expression in sugar beet. CONCLUSIONS: This work shows that SSH can be successfully employed for the identification and subsequent isolation of tissue specific sugar beet promoters. These promoters are shown to drive strong leaf specific gene expression in transgenic sugar beet. The application of these promoters for expressing resistance improving genes against foliar diseases is discussed.

Beta vulgaris↗

PubMed2002

The TGF-beta--Smad network: introducing bioinformatic tools.

The TGF-beta superfamily is an important class of intercellular signalling molecule, including TGF-beta and bone morphogenetic proteins. Intracellular signalling cascades triggered by these molecules eventually activate transcription factors of the Smad family, which then regulate expression of their respective target genes. This article will discuss the TGF-beta--Smad signalling networks and how these processes are represented in databases of signal transduction and transcription control mechanisms. These databases can provide a well-structured overview of the subject and a basis for advanced bioinformatics analyses to interpret the function of genomic sequences or to analyse signalling networks.

Animals↗

PubMed2002

Isolation and molecular analysis of six taproot expressed genes from sugar beet.

The taproot from sugar beet (Beta vulgaris L.) undergoes a specific developmental process to function as a food storage organ. Suppression Subtractive Hybridization (SSH) was utilized for the isolation of cDNA fragments for taproot expressed genes. Isolation and molecular analysis of six cDNAs encoding the complete gene product revealed that these genes comprise homologues of a drought-inducible linker histone, a homologue of a major latex-like protein, a phosphoenolpyruvate carboxylase kinase, a putative vacuolar processing enzyme, a thaumatin-like protein and an alanine- and glutamic acid-rich protein. All genes are transcribed in taproots while transcription in leaves is low or undetectable.

Beta vulgaris↗