Biology subjects

Iguchi, H.

Publications and source records attributed to Iguchi, H..

3 recordsLinked to original sources

bioRxiv2025

Screening analysis of light-responsive phenotype of leaf bacteria

The phyllosphere is a harsh environment in which microorganisms experience various stresses, many of which are attributed to sunlight. To understand the adaptation strategy of bacteria to the phyllospheric environment under sunlight, we examined light-responsive phenotypes by cultivating leaf bacterial isolates under light. Seven bacterial strains belonging to the genera Massilia, Kocuria, Gordonia, Agromyces, Microbacterium, and Arthrobacter were identified to enhance the production of yellow or red carotenoid pigments under light exposure. Light-responsive phenotypes were further analyzed in Massilia sp. ST22. This bacterium was confirmed to have the ability to colonize as well as produce pigments on plants. Analysis of several forms of stress resistance revealed that light positively affected UV resistance and negatively affected resistance to osmotic pressure and oxidative stress. These results uncover the light-responsive phenotypes of the leaf bacteria and indicate that light regulates several bacterial abilities necessary for plant colonization.

microbiology↗

bioRxiv2019

Targeting of RBM10 to S1-1 Nuclear Bodies: Targeting Sequences and its Biological Significance

RBM10 is an RNA-binding protein that regulates alternative splicing (AS). It localizes to the extra-nucleolar nucleoplasm and S1-1 nuclear bodies (NBs) in the nucleus. We investigated the biological significance of this localization in relation to its molecular function. Our analyses, employing deletion mutants, revealed that RBM10 possesses two S1-1 NB-targeting sequences (NBTSs), one in the KEKE motif region and another in the C2H2 Zn finger (ZnF). These NBTSs act synergistically to localize RBM10 to S1-1 NBs. The C2H2 ZnF not only acts as an NBTS, but is also essential for AS regulation by RBM10. Moreover, RBM10 does not participate in S1-1 NB formation, and without alterations of RBM10 protein levels, its NB-localization changes, increasing as cellular transcriptional activity declines, and vice versa. These results indicate that RBM10 is a transient component of S1-1 NBs and is sequestered in NBs via its NBTSs when cellular transcription decreases. We propose that the C2H2 ZnF exerts its NB-targeting activity when RBM10 is unbound by pre-mRNAs, and that NB-localization of RBM10 is a mechanism to control its AS activity in the nucleus. Note that the previous title of this manuscript was Targeting of RBM10 to S1-1 Nuclear Bodies: Targeting Sequences and its Biological Significance.

molecular biology↗

bioRxiv2018

Inner lumen proteins stabilize doublet microtubules in cilia/flagella

Motile cilia are microtubule-based organelles that play important roles in most eukaryotes. Although it is known that microtubules in cilia are sufficiently stable to withstand their beating motion, it remains unknown how they are stabilized while serving as tracks for axonemal dynein and intraflagellar transport. To address this question, we identified a new class of microtubule-associated proteins, named FAP45 and FAP52, in Chlamydomonas. These proteins are conserved among eukaryotes with motile cilia. Using cryo-electron tomography (cryo-ET) and high-speed atomic force microscopy (HS-AFM), we established that lack of these proteins leads to a loss of inner protrusions in B-tubules and less stable microtubules. These inner protrusions are located near the inner junctions of doublet microtubules and lack of FAP45, FAP52, and FAP20 results in detachment of the B-tubule from the A-tubule, as well as flagellar shortening. These results demonstrated that FAP45 and FAP52 bind to the inside of microtubules and stabilize ciliary axonemes.

cell biology↗