29 January 2020

Policymakers are in danger of sleepwalking into ineffective carbon dioxide removal solutions in the quest to tackle climate change. This paper warns against overreliance on bioenergy with carbon capture and storage (BECCS). 

Research Event

1 April 2020

Considerations of justice and social equity are as important for the circular economy transition as they are in the contexts of low-carbon transitions and digitalization of the economy. This paper sets out the just transition approach, and its relevance in climate change and energy transition debates.

15 April 2020

The actin cytoskeleton is extremely dynamic and supports diverse cellular functions in many physiological and pathological processes, including tumorigenesis. However, the mechanisms that regulate the actin-related protein 2/3 (ARP2/3) complex and thereby promote actin polymerization and organization in cancer cells are not well-understood. We previously implicated the proline-rich 11 (PRR11) protein in lung cancer development. In this study, using immunofluorescence staining, actin polymerization assays, and siRNA-mediated gene silencing, we uncovered that cytoplasmic PRR11 is involved in F-actin polymerization and organization. We found that dysregulation of PRR11 expression results in F-actin rearrangement and nuclear instability in non-small cell lung cancer cells. Results from molecular mechanistic experiments indicated that PRR11 associates with and recruits the ARP2/3 complex, facilitates F-actin polymerization, and thereby disrupts the F-actin cytoskeleton, leading to abnormal nuclear lamina assembly and chromatin reorganization. Inhibition of the ARP2/3 complex activity abolished irregular F-actin polymerization, lamina assembly, and chromatin reorganization due to PRR11 overexpression. Notably, experiments with truncated PRR11 variants revealed that PRR11 regulates F-actin through different regions. We found that deletion of either the N or C terminus of PRR11 abrogates its effects on F-actin polymerization and nuclear instability and that deletion of amino acid residues 100–184 or 100–200 strongly induces an F-actin structure called the actin comet tail, not observed with WT PRR11. Our findings indicate that cytoplasmic PRR11 plays an essential role in regulating F-actin assembly and nuclear stability by recruiting the ARP2/3 complex in human non-small cell lung carcinoma cells.

Knowledge of the molecular events in mitochondrial DNA (mtDNA) replication is crucial to understanding the origins of human disorders arising from mitochondrial dysfunction. Twinkle helicase is an essential component of mtDNA replication. Here, we employed atomic force microscopy imaging in air and liquids to visualize ring assembly, DNA binding, and unwinding activity of individual Twinkle hexamers at the single-molecule level. We observed that the Twinkle subunits self-assemble into hexamers and higher-order complexes that can switch between open and closed-ring configurations in the absence of DNA. Our analyses helped visualize Twinkle loading onto and unloading from DNA in an open-ringed configuration. They also revealed that closed-ring conformers bind and unwind several hundred base pairs of duplex DNA at an average rate of ∼240 bp/min. We found that the addition of mitochondrial single-stranded (ss) DNA–binding protein both influences the ways Twinkle loads onto defined DNA substrates and stabilizes the unwound ssDNA product, resulting in a ∼5-fold stimulation of the apparent DNA-unwinding rate. Mitochondrial ssDNA-binding protein also increased the estimated translocation processivity from 1750 to >9000 bp before helicase disassociation, suggesting that more than half of the mitochondrial genome could be unwound by Twinkle during a single DNA-binding event. The strategies used in this work provide a new platform to examine Twinkle disease variants and the core mtDNA replication machinery. They also offer an enhanced framework to investigate molecular mechanisms underlying deletion and depletion of the mitochondrial genome as observed in mitochondrial diseases.

Cas12a (Cpf1) is an RNA-guided endonuclease in the bacterial type V-A CRISPR-Cas anti-phage immune system that can be repurposed for genome editing. Cas12a can bind and cut dsDNA targets with high specificity in vivo, making it an ideal candidate for expanding the arsenal of enzymes used in precise genome editing. However, this reported high specificity contradicts Cas12a's natural role as an immune effector against rapidly evolving phages. Here, we employed high-throughput in vitro cleavage assays to determine and compare the native cleavage specificities and activities of three different natural Cas12a orthologs (FnCas12a, LbCas12a, and AsCas12a). Surprisingly, we observed pervasive sequence-specific nicking of randomized target libraries, with strong nicking of DNA sequences containing up to four mismatches in the Cas12a-targeted DNA-RNA hybrid sequences. We also found that these nicking and cleavage activities depend on mismatch type and position and vary with Cas12a ortholog and CRISPR RNA sequence. Our analysis further revealed robust nonspecific nicking of dsDNA when Cas12a is activated by binding to a target DNA. Together, our findings reveal that Cas12a has multiple nicking activities against dsDNA substrates and that these activities vary among different Cas12a orthologs.

In bacteria, the restart of stalled DNA replication forks requires the DNA helicase PriA. PriA can recognize and remodel abandoned DNA replication forks, unwind DNA in the 3'-to-5' direction, and facilitate the loading of the helicase DnaB onto the DNA to restart replication. Single-stranded DNA–binding protein (SSB) is typically present at the abandoned forks, but it is unclear how SSB and PriA interact, although it has been shown that the two proteins interact both physically and functionally. Here, we used atomic force microscopy to visualize the interaction of PriA with DNA substrates with or without SSB. These experiments were done in the absence of ATP to delineate the substrate recognition pattern of PriA before its ATP-catalyzed DNA-unwinding reaction. These analyses revealed that in the absence of SSB, PriA binds preferentially to a fork substrate with a gap in the leading strand. Such a preference has not been observed for 5'- and 3'-tailed duplexes, suggesting that it is the fork structure that plays an essential role in PriA's selection of DNA substrates. Furthermore, we found that in the absence of SSB, PriA binds exclusively to the fork regions of the DNA substrates. In contrast, fork-bound SSB loads PriA onto the duplex DNA arms of forks, suggesting a remodeling of PriA by SSB. We also demonstrate that the remodeling of PriA requires a functional C-terminal domain of SSB. In summary, our atomic force microscopy analyses reveal key details in the interactions between PriA and stalled DNA replication forks with or without SSB.

A discussion marking the 25th anniversary of the 1990 Immigration Act, where experts examinine the history of the legislation, how it was accomplished politically, and the stakeholders and issues that were critical to its passage.

A discussion featuring data on immigration trends and the agricultural workforce, and some of the adjustments that farm employers are making, including increased mechanization, improved wages and benefits, and the increased use of the H-2A program. University of California-Davis’s Phil Martin, along with researchers from the the U.S. Department of Agriculture, U.S. Department of Labor, present their findings on the foreign agricultural workforce in the United States, which is followed by comments from the President of Farmworker Justice on some of the policy implications.

As policymakers in a number of countries, the United States among them, debate limiting family-based immigration, this issue brief explores family-migration trends and policies in the United States, Australia, Canada, the United Kingdom, and several other European countries. Family admissions play a key role, even in countries that prioritize economic or other immigration streams.

This MPI Europe webinar examines innovative ways to better design and implement predeparture orientation programs for resetttling refugees. The discussion features observations from a refugee who went through an orientation program before being resettled in the Netherlands, and a resettlement agency official in Norway.

As the U.S. health-care system sags under the strain of the COVID-19 pandemic, health-care workers are not only on the frontlines fighting the virus, they are also some of the most at-risk individuals, making it more essential than ever to have sufficient numbers of qualified health professionals. While 1.5 million immigrants and refugees are already working in the U.S. health-care system, an additional 263,000 immigrants and refugees in the U.S. with health-related college degrees are working in low-skilled jobs or are out of work.

What President Trump calls a border crisis is in fact a crisis in the asylum system—one worsened at every turn by his administration’s harsh policies and rhetoric. Rather than spend $5.7 billion on a wall, it would be far more effective to use the money to retool an overwhelmed asylum system, adapt outmatched border enforcement infrastructure to respond to the changing composition of arrivals, and work cooperatively with Mexico to tackle the factors propelling Central Americans to flee.

Though a faceoff between the U.S. executive and legislative branches is now in the courts, with President Trump's decision to declare a national emergency so he can allocate more money for construction of a border wall, a less-noted dispute has been taking place over the Department of Homeland Security's decision to add thousands more immigration detention beds than Congress provides annually, as this article explains.

The House is set to vote on two bills that would largely dismantle the U.S. asylum system at the southern border by significantly narrowing grounds to apply for asylum, eliminating protections for the vast majority of unaccompanied minors, and unilaterally declaring Mexico a safe third country. The result would be a sharp reduction in the number of people permitted to seek humanitarian protection, as this commentary explains.

In exchange for resolving the status of DREAMers, the White House and its congressional allies are demanding billions of dollars for a border wall and additional enforcement, sharp limits on asylum, cuts to legal immigration, and more. But what would the two bills expected to be voted on by the House do in terms of extending temporary or permanent status to DREAMers? This commentary offers estimates.

During its first year, the Trump administration methodically put in place a series of bureaucratic barriers that could significantly reduce opportunities for foreigners to come to the United States legally. Among the actions taken during 2017: Imposition of a much-challenged travel ban suspending the entry of nationals from certain Muslim-majority countries, cuts to refugee admissions, and increased scrutiny for visa applicants.

Award winners for the inaugural year of the E Pluribus Unum Prizes program were honored at a reception at the Library of Congress in Washington, DC in 2009.

This awards ceremony, honoring the 2011 recipients of the E Pluribus Unum Prizes — a national awards program for exceptional immigrant integration initiatives — featured panel discussions with the awardees and federal officials and remarks by White House Director of Intergovernmental Affairs Cecilia Muñoz and Assistant Secretary of Education Brenda Dann-Messier.

This awards ceremony, honoring the 2011 recipients of the E Pluribus Unum Prizes -- a national awards program for exceptional immigrant integration initiatives -- featured panel discussions with the awardees and federal officials and remarks by White House Director of Intergovernmental Affairs Cecilia Muñoz and Assistant Secretary of Education Brenda Dann-Messier.

This awards ceremony honored the 2013 winners of the E Pluribus Unum Prizes, which provides $50,000 prizes to exceptional U.S. immigrant integration initiatives. The awardees took part in a panel discussion with White House and state officials, followed by remarks from Congressman Luis Gutierrez and U.S. Senator Amy Klobuchar.

Marking the release of an MPI report, this webinar examines what the growing intersection between U.S. immigration and child welfare systems means for protection agencies. Speakers also discuss promising child welfare policies and agency approaches to address the needs of children of immigrants and their families amid demographic change and rising immigration enforcement.

High school graduation is a landmark event for students. It also plays an important role in the state accountability systems designed to ensure that schools provide all students a high-quality education. Yet relying on a school's four-year graduation rate for federal accountability purposes can have unintended consequences for English Learners, who may need extra time to graduate.

On the campaign trail, Donald Trump made immigration the centerpiece of his campaign, offering a more detailed policy agenda than on any other issue. In the year since the election that propelled the Republican into the White House, how has the Trump administration’s record matched up with the rhetoric? This policy brief examines the executive orders and other changes to existing policy and practice made during 2017.

The Trump administration has been steadily building a case to penalize "sanctuary" cities—those jurisdictions that in some way limit their cooperation with federal immigration authorities—after threatening to cut federal funding. Despite court rulings that seemed to strike a blow against these efforts, the Justice Department is moving forward with its strategy, relying on a broad interpretation of a federal statute, as this article explores.

The Trump administration took sweeping action in 2018 to slow legal immigration, make life harder for some immigrants already in the United States, rebuff would-be asylum seekers, and reduce refugee resettlement. Shaping a narrative of crisis at the border, the administration significantly changed the U.S. asylum system, deployed troops and tear gas, and separated families—yet Central American migrants continued to arrive.

Remain in Mexico—the Trump administration policy aimed at deterring the rising numbers of migrants from Central America by requiring them to stay in Mexico through most of their U.S. asylum adjudication process—bears striking similarities to U.S. policy in the 1980s and 1990s that sought to discourage Haitians from making the sea journey to the United States. This article explores the parallels and differences between Remain in Mexico and the earlier narrowing of asylum for Haitians.

Approximately 11,500 unaccompanied children were apprehended at the U.S.-Mexico border in May, putting this year on track to exceed 2014's surge. As the U.S. government struggles to care for these child migrants, with public outrage mounting over reports of unsafe, filthy conditions in initial Border Patrol custody, the failure of the executive branch and Congress to plan for increased shelter and care demands are increasingly apparent, as this article explores.

As federal and state governments ramp up efforts to implement the Workforce Innovation and Opportunity Act, these fact sheets compare key characteristics of the foreign born and the U.S. born that are relevant to understanding needs for adult education and workforce training services. The fact sheets cover the United States, the 20 states and 25 counties with the largest immigrant populations, and New York City.

Growing up with unauthorized immigrant parents puts children—nearly 80 percent of whom were born in the United States—at a disadvantage, with lower preschool enrollment, reduced socioeconomic progress, and higher rates of linguistic isolation and poverty. This fact sheet examines the number, characteristics, and socioeconomic status of children, both U.S.-citizen and noncitizen, who have unauthorized immigrant parents.

The immigrant population in the Kansas City region has grown rapidly over the past 25 years, contributing to overall population growth in the area. This fact sheet describes immigrants in the metro area, examining their origins, industries of employment, income and poverty levels, English proficiency, educational attainment, and more.

These fact sheets provide a sketch of key characteristics of the foreign-born and English Learner (EL) populations in select states. The fact sheets look at the demographics of these states, discuss EL student outcomes as measured by standardized tests, and conclude with an overview of state accountability mechanisms that affect ELs under relevant provisions of the Every Student Succeeds Act and predecessor No Child Left Behind Act.

During his first 100 days in office, President Trump has taken a sweeping set of actions on immigration, ranging from imposing a travel ban to cutting refugee admissions, "extreme" vetting, and fortifying immigration enforcement at the border and in the U.S. interior. This fact sheet examines the major immigration actions taken to date, legal challenges, and related policy and personnel developments.