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.

Incorporation of ribonucleotides into DNA can severely diminish genome integrity. However, how ribonucleotides instigate DNA damage is poorly understood. In DNA, they can promote replication stress and genomic instability and have been implicated in several diseases. We report here the impact of the ribonucleotide rATP and of its naturally occurring damaged analog 1,N6-ethenoadenosine (1,N6-ϵrA) on translesion synthesis (TLS), mediated by human DNA polymerase η (hpol η), and on RNase H2–mediated incision. Mass spectral analysis revealed that 1,N6-ϵrA in DNA generates extensive frameshifts during TLS, which can lead to genomic instability. Moreover, steady-state kinetic analysis of the TLS process indicated that deoxypurines (i.e. dATP and dGTP) are inserted predominantly opposite 1,N6-ϵrA. We also show that hpol η acts as a reverse transcriptase in the presence of damaged ribonucleotide 1,N6-ϵrA but has poor RNA primer extension activities. Steady-state kinetic analysis of reverse transcription and RNA primer extension showed that hpol η favors the addition of dATP and dGTP opposite 1,N6-ϵrA. We also found that RNase H2 recognizes 1,N6-ϵrA but has limited incision activity across from this lesion, which can lead to the persistence of this detrimental DNA adduct. We conclude that the damaged and unrepaired ribonucleotide 1,N6-ϵrA in DNA exhibits mutagenic potential and can also alter the reading frame in an mRNA transcript because 1,N6-ϵrA is incompletely incised by RNase H2.

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.

The action mechanisms revealed by the biochemical and structural analyses of replicative and translesion synthesis (TLS) DNA polymerases (Pols) are retained in their cellular roles. In this regard, DNA polymerase θ differs from other Pols in that whereas purified Polθ misincorporates an A opposite 1,N6-ethenodeoxyadenosine (ϵdA) using an abasic-like mode, Polθ performs predominantly error-free TLS in human cells. To test the hypothesis that Polθ adopts a different mechanism for replicating through ϵdA in human cells than in the purified Pol, here we analyze the effects of mutations in the two highly conserved tyrosine residues, Tyr-2387 and Tyr-2391, in the Polθ active site. Our findings that these residues are indispensable for TLS by the purified Pol but are not required in human cells, as well as other findings, provide strong evidence that the Polθ active site is reconfigured in human cells to stabilize ϵdA in the syn conformation for Hoogsteen base pairing with the correct nucleotide. The evidence that a DNA polymerase can configure its active site entirely differently in human cells than in the purified Pol establishes a new paradigm for DNA polymerase function.

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.

With issues of immigration policy very much at the forefront of the 2016 elections, this annual conference offers policy and legal analysis on key immigration topics facing the country and the incoming administration and Congress in 2017.

The 13th annual Immigration Law & Policy Conference offered policy and legal analysis on key immigration topics, including: the election and the future of immigration policy; refugee resettlement in the United States; immigration detention and enforcement; and the impacts of the Supreme Court opinion in the important U.S. vs Texas case

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.

Amid ongoing Brexit negotiations, much remains uncertain for the roughly 1 million UK citizens living elsewhere in the European Union. This report offers a demographic profile of these Brexpats, considering what form an EU-UK deal on citizens’ rights might take and identifying key challenges many Britons are likely to face—including difficulty securing legal status and accessing labor markets, social security, and health-care systems.

With immigration increasingly visible in the news and the political space in the United States and internationally, getting access to accurate, high-quality data is essential to understand immigration’s demographic effects and impacts on the economy, education and labor systems, and communities. This event marks the release of the Immigration Data Matters guide.

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.

Where can you find the most accurate statistics on some of the top immigration issues—ranging from the size of immigrant and emigrant populations, to humanitarian and labor flows, naturalization rates, enforcement statistics, remittances, and more? In this brief video, Jeanne Batalova, who manages the Migration Policy Institute’s Migration Data Hub, walks you through the Immigration Data Matters guide developed by MPI and the Population Reference Bureau.
 

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.

About 2.1 million immigrants work in jobs growing, harvesting, processing, and selling food in the United States, serving an essential role in feeding America. While immigrants accounted for 17 percent of all civilian employed workers in the United States between 2014-18, they played an outsized role in food production, making up 22 percent of workers in the U.S. food supply chain. They represent far larger shares in certain food-related occupations, and in particular states, as this infographic shows.

Marking the release of MPI President Andrew Selee's latest book, speakers explore emerging trends in migration, economic interdependence, technology innovation, and cultural exchange that are transforming the relationship between the United States and Mexico, and the policy implications of these changes for the future.

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.

Even as the 1.8 million number swirls in the discussion of how many DREAMers would be placed on a path to citizenship, proposals debated in the Senate in February 2018 would have resulted in the legalization of smaller numbers, as this commentary explains. It offers estimates of potential beneficiaries of several Senate proposals, including one backed by the White House, and analysis of key criteria.

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.

A report release and presentation of first-ever U.S. estimates on the actual economic costs of skill underutilization for immigrants, their families, and the U.S. economy, in terms of forgone earnings and unrealized federal, state, and local taxes.

More than 1 million international students were in the United States in 2015-16, a significant share of them in science, technology, engineering, or math (STEM) fields. While countries increasingly are vying for this population, these individuals face a complex choice upon graduation: to stay or leave? This article examines international STEM students in the United States and the motivations underlying their postgraduation plans.

In 2015, 43.3 million immigrants lived in the United States, comprising 13.5 percent of the population. The foreign-born population grew more slowly than in prior years, up 2 percent from 2014. Get sought-after data on U.S. immigration trends, including top countries of origin, Mexican migration, refugee admissions, illegal immigration, health-care coverage, and much more in this Spotlight article.

Over the past decade, immigrant investor programs have proliferated around the world, and Chinese applicants have dominated in a number of countries. In 2015, about 9,000 Chinese millionaires moved to other countries, many through so-called golden visa programs. This article explores the social and cultural factors driving well-off Chinese to move abroad and examines perceptions of elite emigration in China.

The United States is by far the world's top migration destination, home to roughly one-fifth of all global migrants. In 2016, nearly 44 million immigrants lived in the United States, comprising 13.5 percent of the country's population. Get the most sought-after data available on immigrants and immigration trends, including top countries of origin, legal immigration pathways, enforcement actions, health-care coverage, and much more.

At this release of an updated version of the popular Immigration Data Matters guide, presenters discuss how to navigate and access the increasing number of data sources on immigration and immigrants in the United States and internationally. 

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.

Faced with a lack of employment opportunities and recurrent poverty, Albanian youth migrate to Italy alone in the hopes of improving their educational prospects or making money for their families. Yet upon arrival, they face many vulnerabilities. While some protections for unaccompanied minors exist in the Italy, the system is greatly fragmented and challenges, including how to return them to Albania, remain persistent.

The Trump administration’s decision to terminate the Deferred Action for Childhood Arrivals (DACA) deportation-relief program launched in 2012 has sparked new urgency to find a longer-term fix for "DREAMers," the unauthorized immigrants brought to the United States as children. This Policy Beat article examines movement in the courts and in Congress on the DREAM Act and similar proposals, exploring likely paths forward.

In a year when immigration has been prominent in the headlines, the 14th annual Immigration Law and Policy Conference provides timely policy and legal analysis, with expert discussion covering the shifting immigration policy priorities under a new administration, including changes in immigration enforcement, border enforcement, refugee resettlement, the treatment of unaccompanied minors and their families, Temporary Protected Status, and DACA, along with the responses from the judicial and congressional branches, various stakeholders, and state and local governments. 

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 significantly cranked up the immigration enforcement machinery in the U.S. interior. Yet even as arrests and deportations are up in the early Trump months, they remain less than half their peaks. This report demonstrates how pushback from California and other "sanctuary" locations makes it quite unlikely that ICE will be able to match record enforcement levels.

Discussion at this event focused on findings from MPI's report examining the interior immigration enforcement system in the United States, including ICE data on deportations and arrests, and the responses of state and local governments, civil society, and consulates.  

At a time of intense and fast-moving action on immigration, 2018's Immigration Law and Policy Conference offered an excellent opportunity to go beyond the headlines with thoughtful analysis from leading experts.

At the 15th annual Immigration Law and Policy Conference, held in October 2018, leading experts and government officials discussed the role that immigration is playing in the mid-term elections; how the courts are handling key immigration questions; and recent changes in the U.S. asylum system, border and interior enforcement, and regulations surrounding legal immigration.   

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.

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.

This fact sheet uses U.S. and Mexican apprehensions data to trace the evolving trends in unaccompanied child and family migration from Central America through Mexico and to the United States, and discusses the push factors and pull factors responsible for the increase in flows seen in recent years, as well as the growing role of smuggling organizations.

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.

As the share of U.S. children under age 8 who are Dual Language Learners (DLLs) increases, state policies have an important role to play in ensuring all young learners are able to get their education off to a good start. These fact sheets compare key characteristics of DLLs and their peers nationwide and in 30 states, and identify state policies that support equitable access to high-quality early childhood education and care programs.

A high school diploma has been a core requirement of proposed DREAM Act legislation and the Deferred Action for Childhood Arrivals (DACA) program. Yet a fresh estimate of the number of unauthorized immigrants graduating annually from U.S. high schools has long been missing from the debate. This fact sheet provides up-to-date estimates for the United States and top 15 states, estimating 98,000 such students graduate yearly.

This meeting highlighted lessons from MPI Europe’s flagship Integration Futures initiative, which seeks to develop creative and strategic approaches to addressing today’s most difficult and pressing integration challenges—and to better plan for those around the corner.

The third Social Innovation for Refugee Inclusion conference in Brussels, co-organized by MPI Europe with the U.S. and Canadian Missions to the European Union and the European Economic and Social Committee, explored how innovations in living situations for refugees can promote community-driven inclusion, overcome divisions, facilitate economic opportunities, and foster a sense of "home."