Overexpression of a truncated CTF7 construct leads to pleiotropic defects in reproduction and vegetative growth in Arabidopsis

Abstract

BackgroundEco1/Ctf7 is essential for the establishment of sister chromatid cohesion during S phase of the cell cycle. Inactivation of Ctf7/Eco1 leads to a lethal phenotype in most organisms. Altering Eco1/Ctf7 levels or point mutations in the gene can lead to alterations in nuclear division as well as a wide range of developmental defects. Inactivation of Arabidopsis CTF7 (AtCTF7) results in severe defects in reproduction and vegetative growth.ResultsTo further investigate the function(s) of AtCTF7, a tagged version of AtCTF7 and several AtCTF7 deletion constructs were created and transformed into wild type or ctf7+/–plants. Transgenic plants expressing 35S:NTAP:AtCTF7∆299–345 (AtCTF7∆B) displayed a wide range of phenotypic alterations in reproduction and vegetative growth. Male meiocytes exhibited chromosome fragmentation and uneven chromosome segregation. Mutant ovules contained abnormal megasporocyte-like cells during pre-meiosis, megaspores experienced elongated meiosis and megagametogenesis, and defective megaspores/embryo sacs were produced at various stages. The transgenic plants also exhibited a broad range of vegetative defects, including meristem disruption and dwarfism that were inherited in a non-Mendelian fashion. Transcripts for epigenetically regulated transposable elements (TEs) were elevated in transgenic plants. Transgenic plants expressing 35S:AtCTF7∆B displayed similar vegetative defects, suggesting the defects in 35S:NTAP:AtCTF7∆B plants are caused by high-level expression of AtCTF7∆B.ConclusionsHigh level expression of AtCTF7∆B disrupts megasporogenesis, megagametogenesis and male meiosis, as well as causing a broad range of vegetative defects, including dwarfism that are inherited in a non-Mendelian fashion.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0452-2) contains supplementary material, which is available to authorized users.

The Opposing Actions of Arabidopsis CHROMOSOME TRANSMISSION FIDELITY7 and WINGS APART-LIKE1 and 2 Differ in Mitotic and Meiotic Cells

“…They facilitate long-distance DNA interactions (Dorsett and Merkenschlager, 2013) and have been shown to affect long-range interactions between binding sites of the transcriptional repressor CTCF in a number of genes in animal cells (Bonora et al, 2014). Consistent with this, alterations in cohesin protein levels can result in tissue-specific alterations in transcript levels for a number of genes in Arabidopsis (this study; Yuan et al, 2012;Bolaños-Villegas et al, 2013;Liu and Makaroff, 2015). For example, transgenic plants expressing a pro35S:AtCTF7ΔB construct and ctf7 plants contain elevated levels of transcripts for epigenetically regulated transposable elements, including MU1, COPIA 28, and solo LTR, and alterations in transcript levels of several small interfering RNA-associated genes (Bolaños-Villegas et al, 2013;Liu and Makaroff, 2015).…”

“…Consistent with this, alterations in cohesin protein levels can result in tissue-specific alterations in transcript levels for a number of genes in Arabidopsis (this study; Yuan et al, 2012;Bolaños-Villegas et al, 2013;Liu and Makaroff, 2015). For example, transgenic plants expressing a pro35S:AtCTF7ΔB construct and ctf7 plants contain elevated levels of transcripts for epigenetically regulated transposable elements, including MU1, COPIA 28, and solo LTR, and alterations in transcript levels of several small interfering RNA-associated genes (Bolaños-Villegas et al, 2013;Liu and Makaroff, 2015). Therefore, it is possible that inactivation of CTF7 and/or WAPL results in chromatin conformational changes that alter transcriptional patterns and cause the embryo arrest we observe.…”

AtNUF2 modulates spindle microtubule organization and chromosome segregation during mitosis

“…It was reported that post‐embryonic vegetative growth is also important for plant development (Huang et al ., 2015; Liu and Makaroff, 2015). In higher plants, SAM and RAM are composed of primary stem cells that continuously produce daughter cells for tissue differentiation and organ formation (Gaillochet and Lohmann, 2015; Greb and Lohmann, 2016).…”

In Favor of Establishment: Regulation of Chromatid Cohesion in Plants

“…Similar phenotypes were observed in plants transformed with a dexamethasone-inducible CTF7 -RNAi construct. Finally, overexpression of the CTF7 genomic sequence leads to ovule arrest at female gametophyte 1 stage ( Liu and Makaroff, 2015 ).…”