The phytochrome (phy) family of plant photoreceptors controls various aspects of photomorphogenesis. Overexpression of rice phyA-green fluorescent protein (GFP) and tobacco phyB-GFP fusion proteins in tobacco results in functional photoreceptors. phyA-GFP and phyB-GFP are localized in the cytosol of dark-adapted plants. In our experiments, red light treatment led to nuclear translocation of phyA-GFP and phyB-GFP, albeit with different kinetics. Red light-induced nuclear import of phyB-GFP, but not that of phyA-GFP, was inhibited by far-red light. Far-red light alone only induced nuclear translocation of phyA-GFP. These observations indicate that nuclear import of phyA-GFP is controlled by a very low fluence response, whereas translocation of phyB-GFP is regulated by a low fluence response of phytochrome. Thus, light-regulated nucleocytoplasmic partitioning of phyA and phyB is a major step in phytochrome signaling.

The phytochrome (phy) family of plant photoreceptors controls various aspects of photomorphogenesis. Overexpression of rice phyA-green fluorescent protein (GFP) and tobacco phyB-GFP fusion proteins in tobacco results in functional photoreceptors. phyA-GFP and phyB-GFP are localized in the cytosol of dark-adapted plants. In our experiments, red light treatment led to nuclear translocation of phyA-GFP and phyB-GFP, albeit with different kinetics. Red light-induced nuclear import of phyB-GFP, but not that of phyA-GFP, was inhibited by far-red light. Far-red light alone only induced nuclear translocation of phyA-GFP. These observations indicate that nuclear import of phyA-GFP is controlled by a very low fluence response, whereas translocation of phyB-GFP is regulated by a low fluence response of phytochrome. Thus, light-regulated nucleocytoplasmic partitioning of phyA and phyB is a major step in phytochrome signaling.

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Summary Phytochromes (phy) are a family of photoreceptors that control various aspects of light‐dependent plant development. Phytochrome A (phyA) is responsible for the very low fluence response (VLFR) under inductive light conditions and for the high irradiance response (HIR) under continuous far‐red light. We have recently shown that nuclear import of rice phyA:GFP is regulated by VLFR in transgenic tobacco. The import is preceded by very fast, light‐induced formation of sequestered areas of phyA:GFP in the cytosol. Here we report that expression of the Arabidopsis phyA:GFP fusion protein in phyA‐deficient Arabidopsis plants complements the mutant phenotype. In these transgenic Arabidopsis lines, both light‐dependent cytosolic formation of sequestered areas of the phyA:GFP as well as VLFR or HIR‐mediated nuclear import of the fusion protein was observed. By contrast, light‐dependent nuclear import of the same fusion protein was induced only by continuous far‐red light (HIR) but not by pulses of far‐red light (VLFR) in transgenic tobacco. These results demonstrate that photoregulation of intracellular partitioning of the Arabidopsis phyA:GFP differs significantly in different genetic backgrounds.

LI-cadherin (Liver-Intestine cadherin) is a member of a subclass (7-D cadherins) within the cadherin superfamily. Although its cellular function as a cell-cell adhesion molecule has been demonstrated in cell culture studies, its physiological function still needs to be explored in the intact organism. After isolating the cDNA for mouse LI-cadherin, we generated specific antibodies against the overexpressed protein and studied its expression pattern in adult mouse tissues and mouse embryos. The mouse LI-cadherin sequence is 91% identical to the sequence of rat LI-cadherin and exhibits the same structural features described for rat LI-cadherin. In mouse adult tissue, LI-cadherin is expressed in the intestine and in small amounts in the spleen. In contrast to rat, Mouse LI-cadherin was not expressed in liver. During mouse embryogenesis, LI-cadherin expression begins at embryonic day 12.5. With the exception of transient expression in the urogenital sinus and the common bile duct on day 13.5, LI-cadherin was found exclusively in the intestinal epithelium. Its expression coincides with the formation of intestinal villi, a developmental stage that includes major tissue remodeling, growth, and differentiation. LI-cadherin is expressed along the entire anterior-posterior axis of the developing intestine as well as along the entire villus axis once villi begin to form. LI-cadherin occupies all cell surfaces of the deeper layers of the epithelium, distributing to basolateral surfaces only in the cells of the outer epithelial layer. LI-cadherin was found to be always coexpressed with E-cadherin.

Defining the complex role of the microbiome in colorectal cancer and the discovery of novel, protumorigenic microbes are areas of active investigation. In the present study, culturing and reassociation experiments revealed that toxigenic strains of Clostridioides difficile drove the tumorigenic phenotype of a subset of colorectal cancer patient–derived mucosal slurries in germ-free ApcMin/+ mice. Tumorigenesis was dependent on the C. difficile toxin TcdB and was associated with induction of Wnt signaling, reactive oxygen species, and protumorigenic mucosal immune responses marked by the infiltration of activated myeloid cells and IL17-producing lymphoid and innate lymphoid cell subsets. These findings suggest that chronic colonization with toxigenic C. difficile is a potential driver of colorectal cancer in patients. Significance: Colorectal cancer is a leading cause of cancer and cancer-related deaths worldwide, with a multifactorial etiology that likely includes procarcinogenic bacteria. Using human colon cancer specimens, culturing, and murine models, we demonstrate that chronic infection with the enteric pathogen C. difficile is a previously unrecognized contributor to colonic tumorigenesis.

Parenting tends to be framed as a set of actions directed toward the child rather than as a relationship. This article helps therapists, parent-educators, and researchers conceptualize parenting as a socioculturally embedded relationship. The authors apply the relational orientations typology (Silverstein, Bass, Tuttle, Knudson-Martin, & Huenergardt, 2006) to parent-child relationships. The typology addresses two dimensions: whether the focus is on the child's meeting parental expectations or on expectations of mutuality and whether power between parent and child is expected to be symmetrical or asymmetrical. Four relational orientations are described: (1) rule directed, (2) position directed, (3) independence directed, and (4) relationship directed. These relational orientations describe the nature of the reciprocal relationship between parent and child and offer a framework from which to address parenting issues. A case illustration shows how the relational orientations framework helps therapists incorporate a larger systems/relational perspective into what was originally framed primarily as a child behavior problem.

Increasingly, couple therapists are called to promote equity in their clinical practice, yet little research illuminates the intricacy of doing this work. The purpose of this study was to clarify the clinical processes involved when therapists facilitate a more equitable balance of power in couple relationships while utilizing a sociocontextual frame of reference. It is part of larger research explicating Socio‐Emotional Relationship Therapy (SERT), an approach that places equity and social justice at the core. The sample included 72 SERT sessions with nine heterosoexual couples in which there was an observable power difference between partners. Using Charmaz’s (2014, Constructing grounded theory: A practical guide through qualitative analysis, Sage) grounded theory coding, theoretical sampling, and interpretive methods, we examined therapist/client responses over multiple sessions to explain shifts in the couples’ power balance. Analysis identified sociocultural attunement to vulnerability as the core clinical process and detailed five sociocultural expressions: socialized vulnerability, socialized invulnerability, reactive (in)vulnerability, reactive vulnerability, and shared vulnerability. Shifts in power involved each of three therapist stances: (a) identification of the societal power context of vulnerability, (b) therapist leadership and responsive persistence, and (c) facilitating mutual sociocultural attunement to vulnerability to promote shared relational responsibility and influence. Implications address the connections between power and vulnerability in couples work and what therapists can do to more effectively facilitate relational equity.