Different functions of the histone acetyltransferase HAC1 gene traced in the model species Medicago truncatula, Lotus japonicus and Arabidopsis thaliana

Abstract

In eukaryotes, histone acetyltransferases regulate the acetylation of histones and transcription factors, affecting chromatin structural organization, transcriptional regulation, and gene activation. To assess the role of HAC1, a gene encoding for a histone acetyltransferase in Medicago truncatula, stable transgenic lines with modified HAC1 expression in the model plants M. truncatula, Lotus japonicus, and Arabidopsis thaliana were generated by Agrobacterium-mediated transformation and used for functional analyses. Histochemical, transcriptional, flow cytometric, and morphological analyses demonstrated the involvement of HAC1 in plant growth and development, responses to internal stimuli, and cell cycle progression. Expression patterns of a reporter gene encoding beta-glucuronidase (GUS) fused to the HAC1 promoter sequence were associated with young tissues comprised of actively dividing cells in different plant organs. The green fluorescent protein (GFP) signal, driven by the HAC1 promoter, was detected in the nuclei and cytoplasm of root cells. Transgenic lines with HAC1 overexpression and knockdown showed a wide range of phenotypic deviations and developmental abnormalities, which provided lines of evidence for the role of HAC1 in plant development. Synchronization of A. thaliana root tips in a line with HAC1 knockdown showed the involvement of this gene in the acetylation of two core histones during S phase of the plant cell cycle.

Identification of genomic regions associated with multi-silique trait in Brassica napus

“…So the different expression of BnaC08g41780D between zws-ms and zws-217 may result some unknown process in fruit development. (3) The knockdown of HAC1 causes disturbances in flower morphology in the Arabidopsis , such as a modified petal shape or even absence of petals [42]. HAC12 has high identity with HAC1 , but what morphology changes it can make are still unknown.…”

Comparison of efficiency and time to regeneration of Agrobacterium-mediated transformation methods in Medicago truncatula

“…Agrobacterium-mediated transformation is ecotype dependent in many plants, as ecotypes respond differently with varying transformation efficiencies (transgenic plants/initial calli formed) [13–16]. The A17 ecotype of M. truncatula serves as the reference accession for the genome [17] and although used widely in labs, it is considered difficult to transform [18].…”

Genome-Wide Identification of Histone Modification Gene Families in the Model Legume Medicago truncatula and Their Expression Analysis in Nodules

“…The ZZ domain is relatively small in size and recent work has shown its role in binding the N-terminus of H3, allowing histone acetylation as well as methylation [50]. The HAC1 gene which was reported by [29], corresponding to Medtr7g105680.1 (Mt4.01), although showing a low degree of similarity with AtHAC1 (Blast-P score 121, 41% query cover, 2 × 10 −28 E-value, 37.5% identity), was not revealed by our analysis because it does not harbor a PF08214 domain.…”

“…A recent functional analysis of the three HDTs by RNAi knock-down that is restricted to nodules demonstrated that they play a key role in primordium formation and nodule development, because both meristem size and cell colonization by bacteria was reduced [28]. Another functional report for the gene HAC1 in M. truncatula, obtained by RNAi downregulation and gene over-expression, showed a range of alterations in plant organ development, supporting a fundamental role for the gene [29]. The expression of the MtJMJC5 gene, a putative Arabidopsis JMJ30/JMJD5 ortholog, was characterized during the circadian rhythm and shown to be oscillating with alternative splicing occurring under cold induction; no functional analysis was provided [30].…”