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C Kuhlemeier

Publications and source records attributed to C Kuhlemeier.

29 records · Page 2Linked to original sources
PubMed1993

Long-term anoxia tolerance. Multi-level regulation of gene expression in the amphibious plant Acorus calamus L.

Acorus calamus is a monocotyledonous wetland plant that can withstand extremely long periods of anoxia. We have investigated the expression of genes coding for pyruvate decarboxylase (Pdc), alcohol dehydrogenase (Adh), and fructose-1,6-bisphosphate aldolase (Ald) during periods of anoxia ranging from 2 h to 2 months. Upon anoxic incubation, Pdc mRNA levels peak at 6 h, followed by Adh and Ald, which peak at 12 and 72 h, respectively. Subsequently, the mRNA levels of all three genes decline within days to low levels. In contrast, alcohol dehydrogenase (ADH) protein levels increase steadily for at least a week and then remain constant. Native gel electrophoresis demonstrates the presence of two sets of ADH isozymes, one present constitutively, the other enhanced during anoxia. Translation initiation factor 4A protein levels, used as a control, remain constant during 2 months of anoxia. The results suggest that A. calamus has developed a complex anaerobic response consisting of differential regulation of transcription, translation, and posttranslational processes.

Alcohol Dehydrogenase↗
PubMed1993

The patterns of gene expression in the tomato shoot apical meristem.

In this paper, we describe the synthesis of a cDNA library from the vegetative shoot apical meristem and the analysis of clones selected from it. Using in situ hybridization, we characterized the patterns of expression of these genes in the tomato shoot apical meristem, as well as the patterns obtained from other sources. The results from the analysis of 15 cDNAs indicated the following six main patterns of gene expression in the shoot apical meristem: overall expression, zero expression, expression limited to the epidermis, expression excluded from the epidermis, punctate expression, and expression elevated in the flanks of the meristem. The patterns observed and the nature and number of the genes showing these patterns necessitate a reinterpretation of the models of meristem structure and function. In particular, the data suggest a compartmentation within the shoot apical meristem based on the spatial expression of particular subsets of genes. This paper also reports on the specific and precise criteria essential for the correct identification of meristem-specific gene expression. The data give new insight into the molecular organization of the shoot apical meristem and provide the framework for a detailed dissection of the factors controlling this organization.

Amino Acid Sequence↗
PubMed1992

Differential expression of genes encoding the hypusine-containing translation initiation factor, eIF-5A, in tobacco.

Two Nicotiana plumbaginifolia cDNA clones, NeIF-5A1 and NeIF-5A2, encoding eukaryotic translation initiation factor eIF-5A (formerly called eIF-4D) were cloned by heterologous screening with Dictyostelium and human eIF-5A probes. eIF-5A is the only protein known to contain a unique amino acid modification, hypusine. Comparison of the Nicotiana deduced amino acid sequences with those of other eIF-5A polypeptides reveals conservation throughout the coding sequence, especially in the region of the hypusine residue. Transcript analysis reveals that NeIF-5A1 is preferentially expressed in photosynthetic tissues, while NeIF-5A2 is constitutively expressed in all plant tissues examined. A polyclonal antibody was raised against NeIF-5A1 overexpressed in E. coli. NeIF-5A1 antiserum crossreacts with an 18 kDa polypeptide doublet in all tobacco tissues examined. At least one polypeptide of ca. 18 kDa from a diversity of higher and lower plants crossreacts with NeIF-5A1 antiserum.

Amino Acid Sequence↗
PubMed1992

Expression pattern of a tobacco lipid transfer protein gene within the shoot apex.

A genomic clone coding for a putative lipid transfer protein was isolated from Nicotiana tabacum. The gene is expressed in all aerial organs of the tobacco plant, with expression being highest in the upper part of the plant and declining towards the base (i.e. with increasing age). In the shoot apex transcript levels are highest in the LI layer, lower in the underlying cell layers, and are again higher in the submeristem region. This pattern is markedly different from those previously described for genes expressed within the shoot apex.

Amino Acid Sequence↗
PubMed1991

Divergent genes for translation initiation factor eIF-4A are coordinately expressed in tobacco.

Three cDNA clones coding for eukaryotic translation initiation factor 4A, eIF-4A, were isolated from a Nicotiana plumbaginifolia root cDNA library by heterologous screening. The clones comprise two distinct gene classes as two clones are highly similar while the third is divergent. The genes belong to a highly conserved gene family, the DEAD box supergene family, although the divergent clone contains a DESD box rather than the characteristic DEAD box. The two clones are representatives of separate small multigene families in both N. plumbaginifolia and N. tabacum. Representatives of each family are coordinately expressed in all plant organs examined. The 47 kD polypeptide product of one clone, overexpressed in E. coli, crossreacts immunologically with a rabbit reticulocyte eIF-4A polyclonal antibody. Taken together the data suggest that the two Nicotiana eIF-4A genes encode translation initiation factors. The sequence divergence and the coordinate expression of the two Nicotiana eIF-4A families provide an excellent system to determine if functionally distinct eIF-4A polypeptides are required for translation initiation in plants.

Amino Acid Sequence↗
PubMed1990

Minimal sequence requirements for the regulated expression of rbcS-3A from Pisum sativum in transgenic tobacco plants.

RbcS-3A, the most highly expressed member of the pea multigene family encoding the small subunit of ribulose 1,5-bisphosphate carboxylase, is expressed in a light-dependent and organ-specific manner. In order to further delineate the sequences which mediate this complex pattern of regulation, putative regulatory sequences were assayed for function in transgenic tobacco plants in the context of an inactive 5' deleted rbcS-3A test gene. We have identified a minimal functional unit of 58 bp which is able to confer organ-specific transcriptional activity. It contains two sequences conserved among the pea rbcS family members, namely box II (-151 to -138; GTGTGGTTAATATG) and box III (-125 to -114; ATCATTTTCACT). These sequences bind the nuclear factor termed GT-1 in vitro. Substitution mutations within this 58 bp element have demonstrated that sequences upstream of, or located between, boxes II and III are not required for the transcriptional activity conferred by this element. Distance and orientation of these sequences from the gene are not critical for activity within the limits tested. DNA fragments upstream of nucleotide -170 of rbcS-3A that contain other GT-1 binding sites can also confer regulated expression upon the rbcS-3A promoter deleted to -50. Multimers of individual motifs, namely four tandem copies of boxes II and III, are unable to drive expression of the deleted promoter. These observations suggest that while GT-1 binding is necessary for promoter activity it is by itself not sufficient.

Base Sequence↗
PubMed1988

Localization and conditional redundancy of regulatory elements in rbcS-3A, a pea gene encoding the small subunit of ribulose-bisphosphate carboxylase.

Expression of the pea rbcS-3A gene, one of a family of genes encoding the small subunit of ribulose-bisphosphate carboxylase [EC 4.1.1.39], is regulated by light and is restricted to chloroplast-containing cells. We analyzed the effects of light and development on rbcS-3A expression in transgenic plants. Two highly conserved sequences ("boxes" II and III) around nucleotide position -150 (relative to the transcription initiation site, +1) are required for rbcS-3A expression. The so-defined positive elements overlap with previously identified negative light-regulatory elements. In the case of box II, which has sequence similarity to the core enhancer motif of simian virus 40, a GG----CC transversion is sufficient to abolish expression. The effect of mutations in boxes II and III can only be measured when sequences upstream of -170 are removed, and because sequences both 5' and 3' of -170 can direct light-regulated and organ-specific expression. This implies that there is a redundancy of cis-acting elements in the 5' noncoding region of rbcS-3A. However, we show that the sequences upstream of -170 are dispensable only in the mature leaves of a green plant. In contrast, in the young, expanding leaves at the top of a green plant, as well as in seedlings, the distal elements are required for high-level expression. Therefore, redundancy is not absolute, and the requirements for rbcS-3A expression change during plant development.

Base Sequence↗
PubMed1987

Sequences in the pea rbcS-3A gene have homology to constitutive mammalian enhancers but function as negative regulatory elements.

The pea rbcS-3A gene, which codes for a key component of the photosynthetic machinery, requires light for its expression. Analysis of chimeric constructs in transgenic tobacco plants has shown that a 280-bp fragment from the 5' noncoding region can act as a light-inducible transcriptional enhancer. Further characterization of this enhancer identifies a 58-bp sequence containing two regulatory elements that can decrease transcription in the dark. One has a high degree of homology to the SV40 core enhancer, the other to the adenovirus 5 E1A enhancer and the constitutive part of the human interferon-beta gene enhancer. Deletion of the 58-bp sequence uncovers additional light-responsive elements (LREs) located further upstream and downstream.

Animals↗
PubMed1981

Properties of the A and A proteins of bacteriophage G4. The origin of G4 replicative-form DNA replication.

The A and A proteins of the bacteriophage G4 have been purified. The proteins have been analysed for their enzymatic activities on single-stranded and double-stranded DNA. The A protein introduces a single-stranded break at a specific place in the G4 replicative form I DNA. This cleavage site has been localized between nucleotides 506 and 507 in the viral (+) strand. The A protein binds covalently to the 5' end of the cleavage site. The A protein initiates the replication of the viral (+) DNA [Borrias, et al. (1979) Virology, 31, 288-298]; the cleavage site therefore identifies the origin of replication. The A protein cleaves viral (+) strand DNA at many different sites and also binds covalently to the 5' ends of the nick sites. The properties of both proteins strongly resemble the properties of the A and A proteins of the related and much butter analysed phage phi X174. These results indicate that the G4 and phi X174A and A proteins have comparable functions and also that both phages initiate the replicative form DNA in a similar way.

Base Sequence↗
PubMedDate not supplied

Characterization of nodule-specific cDNA clones from Sesbania rostrata and expression of the corresponding genes during the initial stages of stem nodules and root nodules formation.

We have constructed a Sesbania rostrata stem nodule-specific cDNA library. By screening with heterologous probes from pea and soybean, we have isolated several nodulin cDNA clones. On the basis of nucleotide and amino acid sequence homology, two nearly full-length cDNA clones coding for two different leghemoglobin-like proteins have been identified. The inserts of two other clones reveal a high degree of amino acid sequence homology (81% and 72%) to the early nodulin Enod2 from soybean; the characteristic heptapeptide repeat units PPHEKPP and PPYEKPP of the soybean Enod2 are conserved in the proteins encoded by these Sesbania cDNA clones. The time course of Enod2 and leghemoglobin mRNA appearance during the formation of stem nodules and root nodules on S. rostrata was analyzed by northern blot hybridization. Significant differences were found for the initiation of mRNA accumulation of these nodulins between S. rostrata and soybean.

Amino Acid Sequence↗