Biology subjects

Hara, K.

Publications and source records attributed to Hara, K..

3 recordsLinked to original sources

bioRxiv2018

Structural basis of HEAT-kleisin interactions in the human condensin I subcomplex

ABSTRUCTCondensin I is a multi-protein complex that plays an essential role in mitotic chromosome assembly and segregation in eukaryotes. It is composed of five subunits: two SMC (SMC2 and SMC4), a kleisin (CAP-H) and two HEAT-repeat (CAP-D2 and -G) subunits. Although it has been shown that balancing acts of the two HEAT-repeat subunits enable this complex to support dynamic assembly of chromosomal axes in vertebrate cells, its underlying mechanisms remain poorly understood. Here, we report the crystal structure of a human condensin I subcomplex comprising hCAP-G and hCAP-H. hCAP-H binds to the concave surfaces of a harp-shaped HEAT repeat domain of hCAP-G. A physical interaction between hCAP-G and hCAP-H is indeed essential for mitotic chromosome assembly recapitulated in Xenopus egg cell-free extracts. Furthermore, this study reveals that the human CAP-G-H subcomplex has the ability to interact with not only a double-stranded DNA, but also a single-stranded DNA, implicating potential, functional divergence of the vertebrate condensin I complex in mitotic chromosome assembly.

cell biology↗

bioRxiv2018

Brood-holding causes workers to pay attention to the queen in the carpenter ant Camponotus japonicus

[Abstract]Brood accumulation, a fundamental behavior of offspring care in the carpenter ant Camponotus japonicus, is driven by alternation of holding run and empty-handed run behaviors. In the holding run, a worker holds a brood with her mandibles and carries it to the queen (holding run). After releasing it beside the queen, she hurries back to another brood (empty-handed run). To address the motivation for the brood-accumulation task, in this study, I observed these behaviors under experimental conditions. When workers performed the task in a situation that involved selection between their own and unfamiliar queens, they ran in significantly more restrictive ways during the holding run than during the empty-handed run. Hence, holding represents a different motivational state than empty-handed. In a second experiment, the workers were suddenly presented with an unfamiliar floor during the task. Regardless of whether they were holding or empty-handed, their running traces on the familiar floor were simple, whereas on the unfamiliar floor they were more complex. These results show that holding workers would pay attention to the queen, exploiting cues on the floor to restrict their responses to the queen.

animal behavior and cognition↗

bioRxiv2018

Repeated inversions at the pannier intron drive diversification of intraspecific colour patterns of ladybird beetles

How genetic information is modified to generate phenotypic variation within a species is one of the central questions in evolutionary biology. Here we focus on the striking intraspecific diversity of more than 200 aposematic elytral (forewing) colour patterns of the multicoloured Asian ladybird beetle, Harmonia axyridis, which is regulated by a tightly linked genetic locus h. Our loss-of-function analyses, genetic association studies, de novo genome assemblies, and gene expression data reveal that the GATA transcription factor gene pannier is the major regulatory gene located at the h locus, and suggest that repeated inversions and cis-regulatory modifications at pannier led to the expansion of colour pattern variation in H. axyridis. Moreover, we show that the colour patterning function of pannier is conserved in the seven spotted ladybird beetle, Coccinella septempunctata, suggesting that H. axyridis extraordinary intra-specific variation may have arisen from ancient modifications in a conserved elytral colour patterning mechanisms in ladybird beetles.

evolutionary biology↗