Embryogenesis, which establishes the basic body plan for the post-embryonic organs after stereotyped cell divisions, initiates the first step of the plant life cycle. Studies in the last two decades indicate that embryogenesis is a precisely controlled process, and any defect would result in abnormalities. Here we discuss the recent progresses, with a focus on the cellular pathways governing early embryogenesis in the model species BoldItalic.

Leydig cell (LC) is one of the most important somatic cell types in testis, which localized in the interstitium between seminiferous tubules. The major function of Leydig cells is to produce steroid hormone, androgens. LC differentiation exhibits a biphasic pattern in rodent testes, which are divided into two different temporal mature populations, fetal Leydig cells (FLCs) and adult Leydig cells (ALCs). FLCs are transiently present in fetal testes and undergo involution or degeneration after birth. FLCs are completely devoid and replaced by ALCs in adult testes. Comparing to ALCs, FLCs display unique morphology, ultrastructure and functions. The origin of FLCs has been debated for many years, but it is still a mystery. Many factors have been reported regulating the specification, proliferation and differentiation of FLCs. FLCs degenerate in a few weeks postnatally, however, the underlying mechanism is still unknown. In this review, we will focus on the fate determination of FLCs, and summarize the resent progress on the morphology, ultrastructure, function, origin and involution of FLCs.

The testis exhibits a distinctive form of immune privilege to protect the germ cells from the host immune attack. The property of testicular immune privilege was originally attributed to the blood-testis barrier in the seminiferous epithelium, which sequesters antigens. Recent studies have uncovered several levels of immune control besides the blood-testis barrier involved in the privilege of the testis, including the mechanisms of immune tolerance, reduced immune activation, localized active immunosuppression and antigen-specific immunoregulation. The somatic cells of the testis, especially Sertoli cells, play a key role in regulating the testicular immune privileged status. The constitutive expression of anti-inflammatory factors in the testis by somatic cells is essential for local immunosuppression. Growing evidence shows that androgens orchestrate the inhibition of proinflammatory factors and shift cytokine balance toward a tolerogenic environment. Disruption of these protective mechanisms, which may be caused by trauma, infection and genetic factors, can lead to orchitis and infertility. This review article highlights the unique immune environment of the testis, particularly focuses on the regulation of testicular immune privilege.

In higher plants, specific cell differentiation and fate decision are controlled by differential gene expression. Cell type-specific transcriptome analysis has become an important tool for investigating cell regulatory mechanisms. In recent years, many different techniques have been developed for the isolation of specific cells and the subsequent transcriptome analysis, and considerable data are available regarding the transcriptional profiles of some specific cells. These cell type-specific transcriptome analyses hold significant promise for elucidating the gene expression linked to cellular identities and functions, and are extraordinarily important for research in functional genomics and systems biology aimed toward basic understanding of molecular networks and pathway interactions. Moreover, to reveal the critical mechanisms about sexual plant reproduction, the gamete and embryo cells have long been treated as good subjects for cell-specific transcriptome analysis, and there has been important progress in recent decades. In this review, we summarize current technologies in cell type-specific transcriptome analysis and review the applications of these technologies in research into the mechanisms of sexual reproduction in higher plants.

Pollen is the male gametophyte of seed plants and its tube growth is essential for successful fertilization. Mounting evidence has demonstrated that actin organization and regulation plays a central role in the process of its germination and polarized growth. The native structures and dynamics of actin are subtly modulated by many factors among which numerous actin binding proteins (ABPs) are the most direct and significant regulators. Upstream signals such as Ca²⁺, PIP₂ (phosphatidylinositol-4,5-bis-phosphate) and GTPases can also indirectly act on actin organization through several ABPs. Under such elaborate regulation, actin structures show dynamically continuous modulation to adapt to the BoldItalic biologic functions to mediate secretory vesicle transportation and fusion, which lead to normal growth of the pollen tube. Many encouraging progress has been made in the connection between actin regulation and pollen tube growth in recent years. In this review, we summarize different factors that affect actin organization in pollen tube growth and highlight relative research progress.

The introduction of induced pluripotent stem (iPS) cells has been a milestone in the field of regenerative medicine and drug discovery. iPS cells can provide a continuous and individualized source of stem cells and are considered to hold great potential for economically feasible personalized stem cell therapy. Various diseases might potentially be cured by iPS cell-based therapy including Parkinson’s disease, Alzheimer’s disease, Huntington disease, ischemic heart disease, diabetes and so on. Moreover, iPS cells derived from patients suffering from unique incurable diseases can be developed into patient- and disease-specific cell lines. These cells can be used as an effective approach to study the mechanisms of diseases, providing useful tools for drug discovery, development and evaluation. The development of suitable methods for the culture and expansion of iPS cells and their differentiated progenies make feasible modern drug discovery techniques such as high-throughput screening. Furthermore, iPS cells can be applied in the field of toxicological and pharmacokinetics tests. This review focuses on the applications of iPS cells in the field of pharmaceutical industry.

p53 was discovered 30 years ago. Extensive studies have been done on p53 since then, which makes BoldItalic one of the most extensively studied genes. p53 has long been recognized as a key tumor suppressor. Cell cycle arrest, apoptosis and senescence have been traditionally recognized as the main functions of p53 in tumor suppression. Recently, some novel functions of p53 have been identified, including the regulation of energy metabolism, antioxidant defense, and microRNA expression and maturation, which all contribute to the role of p53 in tumor suppression. Furthermore, the contribution of p53 to normal biologic processes (e.g. reproduction and aging) and some other aspects of diseases (e.g. neurodegenerative diseases) is only now being appreciated. Here we will review recent advances in the study of some new functions of p53.

As a highly conserved class of endogenous small (~22 nucleotides) non-coding RNAs, microRNAs (miRNAs) regulate a broad spectrum of biological processes. Increasing evidences suggested that miRNAs generally regulated gene expression at the posttranscriptional stage via inhibiting the translational process or degrading mRNA. Recent studies have also revealed that there is extensive amount of miRNA, as well as miRNA function-related proteins, in the cell nucleus. Although the molecular basis underneath the biogenesis and function of nucleus miRNAs remains largely unknown, the presence of various miRNAs and miRNA function-related proteins in the nucleus strongly argue that miRNAs may execute their role throughout the whole gene expression pathway. Here we review the recent advances in the researches about the nucleus miRNAs, including the biosynthesis pathways, biological functions and potential regulation machinery of nucleus miRNAs.

Transcriptional regulatory regions are often located several thousand bases from the gene that they control. To function, the chromatin strand forms loops to juxtapose distal regions with the promoter. These long-range chromatin interactions have profound influences on the regulation of gene expression and mapping these interactions is currently a subject of intensive investigation. Chromosome conformation capture (3C) technology and its derivatives have been widely used to detect chromatin interactions and greatly contributed to understanding of the relationship between genome organization and genome function. Here we review these 3C-based methods for the study of long-range chromatin interactions and recent exciting findings obtained by using these technologies.

Amygdala plays a critical role in the regulation of emotional behavior and food intake. Neuropeptides are short chains of amino acids secreted by neurons as intercellular messengers, which regulate different functions such as emotion, food intake, learning and memory. In this review, we summarize the recent progress on the regulation of food intake by amygadala, which is mediated by those neuropeptides known to be critical in the regulation of this process.