Actin Family Proteins in the Human INO80 Chromatin Remodeling Complex Exhibit Functional Roles in the Induction of Heme Oxygenase-1 with Hemin

Origin of Sex-Biased Mental Disorders: Do Males and Females Experience Different Selective Regimes?

The origins of sex-biased differences in disease and health are of growing interest to both medical researchers and health professionals. Several major factors have been identified that affect sex differences in incidence of diseases and mental disorders. These are: sex chromosomes, sex hormones and female immunity, sexual selection and antagonistic evolution, and differential susceptibility of sexes to environmental factors. These factors work on different time scales and are not exclusive of each other. Recently, a combined Sexual Selection-Sex Hormones (SS-SH) Theory was presented as an evolutionary mechanism to explain sex-biased differences in diseases and mental disorders (Singh in J Mol Evol 89:195-213, 2021). In that paper disease prevalence trends were investigated, and non-sex-specific diseases were hypothesized to be more common in males than in females in general. They showed signs of exceptions to this trend with inflammatory diseases and stress-related mental disorders that were more common in females. We believe that the SS-SH theory requires the consideration of psycho-social stress (PSS) to explain the predominance of female-biased mental disorders and some other exceptions in their findings. Here we present a theory of sex-differential experience of PSS and provide quantitative support for the combined SS-SH-PSS Theory using age-standardized incidence rates (ASIRs) recording the levels of male- and female-bias in data obtained from different countries. The grand theory provides an evolutionary framework for explaining patterns of sex-biased trends in the prevalence of disease and health. Further exploration of women's vulnerability to social factors may help to facilitate new treatments for female-biased diseases.

Ino80 is required for H2A.Z eviction from hypha-specific promoters and hyphal development of Candida albicans

ATP‐dependent chromatin remodeling complexes play important roles in many essential cellular processes, including transcription regulation, DNA replication, and repair. Evicting H2A.Z, a variant of histone H2A, from the promoter of hypha‐specific genes is required for hyphal formation in Candida albicans. However, the mechanism that regulates H2A.Z removal during hyphal formation remains unknown. In this study, we demonstrated that Ino80, the core catalytic subunit of the INO80 complex, was recruited to hypha‐specific promoters during hyphal induction in Arp8 dependent manner and facilitated the removal of H2A.Z. Deleting INO80 or mutating the ATPase site of Ino80 impairs the expression of hypha‐specific genes (HSGs) and hyphal development. In addition, we showed that Ino80 was essential for the virulence of C. albicans during systemic infections in mice. Interestingly, Arp5, an INO80 complex‐specific component, acts in concert with Ino80 during DNA damage responses but is dispensable for hyphal induction. Our findings clarified that Ino80 was critical for hyphal development, DNA damage response, and pathogenesis in C. albicans.

Nuclear Actin Dynamics in Gene Expression, DNA Repair, and Cancer

Actin is a highly conserved protein in mammals. The actin dynamics is regulated by actin-binding proteins and actin-related proteins. Nuclear actin and these regulatory proteins participate in multiple nuclear processes, including chromosome architecture organization, chromatin remodeling, transcription machinery regulation, and DNA repair. It is well known that the dysfunctions of these processes contribute to the development of cancer. Moreover, emerging evidence has shown that the deregulated actin dynamics is also related to cancer. This chapter discusses how the deregulation of nuclear actin dynamics contributes to tumorigenesis via such various nuclear events.

Interplay between DNA replication stress, chromatin dynamics and DNA-damage response for the maintenance of genome stability

DNA replication stress is a major source of DNA damage, including double-stranded breaks that promote DNA damage response (DDR) signaling. Inefficient repair of such lesions can affect genome integrity. During DNA replication different factors act on chromatin remodeling in a coordinated way. While recent studies have highlighted individual molecular mechanisms of interaction, less is known about the orchestration of chromatin changes under replication stress. In this review we attempt to explore the complex relationship between DNA replication stress, DDR and genome integrity in mammalian cells, taking into account the role of chromatin disposition as an important modulator of DNA repair. Recent data on chromatin restoration and epigenetic re-establishment after DNA replication stress are reviewed.

The Nature of Actin-Family Proteins in Chromatin-Modifying Complexes

Actin is not only one of the most abundant proteins in eukaryotic cells, but also one of the most versatile. In addition to its familiar involvement in enabling contraction and establishing cellular motility and scaffolding in the cytosol, actin has well-documented roles in a variety of processes within the confines of the nucleus, such as transcriptional regulation and DNA repair. Interestingly, monomeric actin as well as actin-related proteins (Arps) are found as stoichiometric subunits of a variety of chromatin remodeling complexes and histone acetyltransferases, raising the question of precisely what roles they serve in these contexts. Actin and Arps are present in unique combinations in chromatin modifiers, helping to establish structural integrity of the complex and enabling a wide range of functions, such as recruiting the complex to nucleosomes to facilitate chromatin remodeling and promoting ATPase activity of the catalytic subunit. Actin and Arps are also thought to help modulate chromatin dynamics and maintain higher-order chromatin structure. Moreover, the presence of actin and Arps in several chromatin modifiers is necessary for promoting genomic integrity and an effective DNA damage response. In this review, we discuss the involvement of actin and Arps in these nuclear complexes that control chromatin remodeling and histone modifications, while also considering avenues for future study to further shed light on their functional importance.