Targeting of a polytopic membrane protein to the inner envelope membrane of chloroplasts in vivo involves multiple transmembrane segments.

The inner envelope membrane (IEM) of the chloroplast plays crucial roles in forming an osmotic barrier and controlling metabolite exchange between the organelle and the cytosol. The IEM therefore harbours a number of membrane proteins and requires the import and integration of these nuclear-encoded proteins for its biogenesis. Recent studies have demonstrated that the transmembrane segment of single-spanning IEM proteins plays key roles in determining their IEM localization.

Plastid signalling under multiple conditions is accompanied by a common defect in RNA editing in plastids.

Retrograde signalling from the plastid to the nucleus, also known as plastid signalling, plays a key role in coordinating nuclear gene expression with the functional state of plastids. Inhibitors that cause plastid dysfunction have been suggested to generate specific plastid signals related to their modes of action. However, the molecules involved in plastid signalling remain to be identified.

Retrograde signaling pathway from plastid to nucleus.

Plastids are a diverse group of organelles found in plants and some parasites. Because genes encoding plastid proteins are divided between the nuclear and plastid genomes, coordinated expression of genes in two separate genomes is indispensable for plastid function. To coordinate nuclear gene expression with the functional or metabolic state of plastids, plant cells have acquired a retrograde signaling pathway from plastid to nucleus, also known as the plastid signaling pathway.

Coordination of plastid protein import and nuclear gene expression by plastid-to-nucleus retrograde signaling.

Expression of nuclear-encoded plastid proteins and import of those proteins into plastids are indispensable for plastid biogenesis. One possible cellular mechanism that coordinates these two essential processes is retrograde signaling from plastids to the nucleus. However, the molecular details of how this signaling occurs remain elusive.

Identification and characterization of Cor413im proteins as novel components of the chloroplast inner envelope.

Plastids are surrounded by two membrane layers, the outer and inner envelope membranes, which have various transport and metabolic activities. A number of envelope membrane proteins have been identified by biochemical approaches and have been assigned to specific functions. Despite those efforts, the chloroplast envelope membrane is expected to contain a number of as yet unidentified proteins that may affect specific aspects of plant growth and development.

Evaluation of the protective activities of a late embryogenesis abundant (LEA) related protein, Cor15am, during various stresses in vitro.

Arabidopsis Cor15am is a late embryogenesis abundant (LEA) related protein that has been shown to exhibit cryoprotective activity in vitro. In this study, we further investigated the mechanisms by which Cor15am protects substrates from inactivation. Although Cor15am did not exhibit refolding activity, it showed protective activity against various stresses in vitro.

Arabidopsis Cor15am is a chloroplast stromal protein that has cryoprotective activity and forms oligomers.

Many plants acquire increased freezing tolerance when they are exposed to nonfreezing temperatures of a certain duration. This process is known as cold acclimation and allows plants to protect themselves from freezing injury. A wide variety of polypeptides are induced during cold acclimation, among which is one encoded by COR15A in Arabidopsis (Arabidopsis thaliana).

Expression analysis of genes for callose synthases and Rho-type small GTP-binding proteins that are related to callose synthesis in rice anther.

The most chilling-sensitive stage of rice has been found to be at the onset of microspore release. The microsporocytes produce a wall of callose between the primary cell wall and the plasma membrane, and it has been shown that precise regulation of callose synthesis and degradation in anther is essential for fertile pollen formation. In this study, genes for 10 callose synthases in the rice genome were fully annotated and phylogenetically analyzed.

cDNA microarray analysis of rice anther genes under chilling stress at the microsporogenesis stage revealed two genes with DNA transposon Castaway in the 5'-flanking region.

Rice is most chilling sensitive at the onset of microspore release. Chilling treatment at this stage causes male sterility. The gene expression profile during the microspore development process under chilling stress was revealed using a microarray that included 8,987 rice cDNAs.

Maxillae and associated gnathodental specimens of Nacholapithecus kerioi, a large-bodied hominoid from Nachola, northern Kenya.

The middle Miocene large-bodied hominoid from Nachola, initially attributed to Kenyapithecus, was recently transferred to a new genus and species Nacholapithecus kerioi. The hypodigm of N. kerioi consists of numerous maxillae, mandibles, and isolated teeth, as well as a number of postcranial bones.

Molecular cloning and characterization of a novel beta-1,3-glucanase gene from rice.

Beta-1,3-glucanases are referred to as pathogenesis-related proteins and they are also involved in several developmental processes. We isolated a cDNA for beta-1,3-glucanase from rice anther and named it Oryza sativa glucanase 1 (Osg1). Phylogenetic analysis showed that Osg1 belonged to monocotyledonous endo-beta-1,3-glucanase subgroup A.