This study of the Arabidopsis thaliana nitrate transporter NRT1.6 indicated that nitrate is important for early embryo development. Functional analysis of cDNA-injected Xenopus laevis oocytes showed that NRT1.6 is a low-affinity nitrate transporter and does not transport dipeptides. RT-PCR, in situ hybridization, and b-glucuronidase reporter gene analysis showed that expression of NRT1.6 is onl...

Little is known about regulatory factors that act during the earliest stages of plant embryogenesis. The MADS domain protein AGL15 (for AGAMOUS-like) is expressed preferentially during embryogenesis and accumulates during early seed development in monocotyledonous and dicotyledonous flowering plants. AGL15-specific antibodies and immunohistochemistry were used to demonstrate that AGL15 accumula...

Embryoids are initiated from single highly cytoplasmic cells of the stem epidermis of plantlets of Ranunculus sceleratus L. derived from callus cultures. The embryoids show embryological development of the Crucifer type except that the suspensor is reduced or suppressed. The cells of the young embryoids have a large central nucleus surrounded by small vacuoles, a cytoplasm rich in free ribosome...

Factors regulating dynamics of chromatin structure have direct impact on expression of genetic information. Cohesin is a multi-subunit protein complex that is crucial for pairing sister chromatids during cell division, DNA repair and regulation of gene transcription and silencing. In non-plant species, cohesin is loaded on chromatin by the Scc2-Scc4 complex (also known as the NIBPL-MAU2 complex...

Programmed cell death (PCD) has a key role in defence and development of all multicellular organisms. In plants, there is a large gap in our knowledge of the molecular machinery involved at the various stages of PCD, especially the early steps. Here, we identify kiss of death (KOD) encoding a 25-amino-acid peptide that activates a PCD pathway in Arabidopsis thaliana. Two mutant alleles of KOD e...

MOB1 protein is a core component of the Hippo signaling pathway in animals where it is involved in controlling tissue growth and tumor suppression. Plant MOB1 proteins display high sequence homology to animal MOB1 proteins, but little is known regarding their role in plant growth and development. Herein we report the critical roles of Arabidopsis MOB1 (AtMOB1A) in auxin-mediated development in ...

During the endopolyploidization of the suspensor cells of Phaseolus coccineus and P. vulgaris, polytene chromosomes and an important nucleolar apparatus develop within the nuclei. The nucleolus-associated regions of the four nucleolus-organizing chromosomes and the regions of the secondary constrictions (intranucleolar chromatin threads) show a temperature-dependent, reversible variability in t...

MicroRNAs (miRNAs) have emerged as key regulators of gene expression at the post-transcriptional level in both plants and animals. However, the specific functions of MIRNAs (MIRs) and the mechanisms regulating their expression are not fully understood. Previous studies showed that miR160 negatively regulates three genes that encode AUXIN RESPONSE FACTORs (ARF10, -16, and -17). Here, we characte...

Sugar residues in proteoglycan complexes carry important signalling and regulatory functions in biology. In humans, heparan sulphate is an example of such a complex polymer containing glucosamine and N-acetyl-glucosamine residues and is present in the extracellular matrix. Although heparan sulphate has not been found in plants, the At5g13690 gene encoding the alpha-N-acetyl-glucosaminidase (NAG...