Claude Gigot

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The commitment of eukaryotic cells to division normally occurs during the G1 phase of the cell cycle. In mammals D-type cyclins regulate the progression of cells through G1 and therefore are important for both proliferative and developmental controls. Plant CycDs (D-type cyclin homologs) have been identified, but their precise function during the plant cell(More)
Four full-length and one partial cDNA clones encoding four different A-type cyclins were isolated from a tobacco S-phase-specific library. The corresponding mRNAs displayed sequential appearance and disappearance during the cell cycle of highly synchronized suspension-cultured tobacco cells. Sequence analysis showed that the plant A-type cyclins can be(More)
Protein-DNA interactions in the proximal region of an Arabidopsis H4 histone gene promoter were analyzed by DMS in vivo footprinting combined with LMPCR amplification. Interactions were identified over six particular sequence motifs, five of which were previously shown to bind proteins in maize histone H3 and H4 promoters and are commonly found in the(More)
The first complete amino acid sequence of a H1 histone of a monocotyledonous plant was deduced from a cDNA isolated from a maize library. The encoded H1 protein is 245 amino acid-long and shows the classical tripartite organization of this class of histones. The central globular region of 76 residues shows 60% sequence homology with H1 proteins from dicots(More)
Chimeric genes containing the β-glucuronidase (GUS) gene under the control of different Arabidopsis histone H3 and H4 promoters were found to be highly expressed in transient expression experiments using tobacco protoplasts. The activity of one of these promoters, H4A748, was further analyzed. The kinetics of H4A748-GUS activity are very similar to these of(More)
The tissue-specific pattern of expression directed by the H4A748 Arabidopsis histone promoter was investigated by analysis of beta-glucuronidase (GUS) activity in transgenic Arabidopsis containing H4A748-GUS gene fusions. As determined by fluorimetric and histochemical tests, the H4A748 promoter directs preferential expression in meristems of young(More)
Intron-bearing replacement histone H3 genes in Arabidopsis and other plants are highly and constitutively expressed. We demonstrate that the introns located within the 5′-untranslated regions (5′-UTR) of the two Arabidopsis replacement H3 genes will abolish the cell cycle dependence of an endogenous histone H4 promoter. We demonstrate that these introns,(More)
Two histone H3 and two histone H4 genes have been cloned from a λgtWESλ·B Arabidopsis thaliana gene library. From their nucleotide sequences and from studies on their genomic organization, the following conclusions can be drawn: 1) The nucleotide sequences of the two H3 coding regions show only 85% homology, but encode the same proteins. The Arabidopsis H3(More)
Two genes encoding a particular H3 histone variant were isolated from Arabidopsis thaliana. These genes differ from the H3 genes previously cloned from Arabidopsis and other plants by several interesting properties: (1) the two genes are located close to each other; (2) their coding regions are interrupted by two or three small introns, the two closest to(More)
The respective involvement of transcriptional and post-transcriptional mechanisms in coupling H3 and H4 histone gene expression to the S phase of the cell cycle has been studied in synchronized tobacco cells. Induction of histone gene expression at the G1/S transition is shown to be essentially directed by an increase in the transcription rate in response(More)