G2- and early-M-specific expression of the NTCYC1 cyclin gene in Nicotiana tabacum cells

• Published in: Plant molecular biology 1996-12, Vol.32 (6), p.1093-1101
• Main Authors: Qin, L.X. (Paris-Sud Univ., Orsay (France). Inst. de Biotechnologie des Plantes), Perennes, C, Richard, L, Bouvier-Durand, M, Trehin, C, Inze, D, Bergounioux, C
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; Animals; Aphidicolin - pharmacology; BINDING PROTEINS; Biochemistry, Molecular Biology; cell cycle; Cell Cycle Proteins; CELL DIVISION; Cyclins - chemistry; Cyclins - genetics; DIVISION CELLULAIRE; DIVISION CELULAR; DNA; dna content; EXPRESION GENICA; EXPRESSION DES GENES; Flow Cytometry; G2 Phase; genbank/l77082; genbank/l77084; GENE EXPRESSION; Gene Expression Regulation, Plant; Genes, Plant; interphase; Life Sciences; Meiosis; mesophyll; messenger RNA; Mitosis; mitotic cyclins; Molecular Sequence Data; Nicotiana - genetics; Nicotiana - metabolism; NICOTIANA TABACUM; nucleotide sequences; oocytes; Oocytes - cytology; Plant Proteins; Plants, Toxic; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; protoplasts; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Plant - genetics; RNA, Plant - metabolism; Sequence Alignment; structural genes; TRANSFERASAS; TRANSFERASE; TRANSFERASES; Xenopus; Xenopus laevis
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/bf00041393

We have previously reported the isolation of a cDNA encoding a mitotic cyclin, NTCYC1, from a tobacco cell suspension library. Here we describe the expression patterns of NTCYC1 and of Ntsuc1, a suc1 plant homologue, in synchronized tobacco cell suspensions. Furthermore, the expression pattern of this cyclin is compared to that of Ntcdc2-1, a Nicotiana tabacum homologue of cdc2. While no NTCYC1 transcript was detected in cells synchronized in the G1 and S phases, NTCYC1 expression was observed in late G2 and early M phases, disappearing in the G1' of a new cell cycle. On the other hand, Ntsuc1 and Ntcdc2-1 exhibited a constitutive expression during the cell cycle. A functional analysis performed by microinjecting NTCYC1 mRNA into immature Xenopus oocytes, indicates that NTCYC1 could participate in the control of the G2/M transition in plant cells. Subsequently NTCYC1 expression was used to assess the status of mesophyll cells in expanded leaves of N. tabacum. Depending on leaf position along the shoot axis, a large population of mesophyll cells appeared with a 4C DNA content, suggesting a G2 arrest. It was found that leaves with such a population also contained high levels of NTCYC1 transcripts. With respect to these results concerning a naturally occurring G2-arrested cell population, the regulation of NTCYC1 expression in planta is discussed.