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Programming notes

*** Wednesday’s “The Daily Rundown” line-up: NBC’s Michael Isikoff with the latest on the investigation in Boston… Sen. Jeff Flake (R-AZ) on the state of immigration and gun legislation… NBC’s Pete Williams and former National Counterterrorism Center Director Michael Leiter on what we’re learning about the explosives used on Monday… Plus Wilson Center President and former Rep. Jane Harman (D-CA), former RNC Chair Michael Steele and the Financial Times’ Anna Fifield join the Gaggle.

*** Wednesday’s “Jansing & Co.” line-up: MSNBC’s Chris Jansing reports live from Boston and interviews former Oklahoma Gov Frank Keating (R), former New York Gov. George Pataki (R), Boston Globe reporter Kevin Cullen and former FBI profiler Clint Van Zandt.

*** Wednesday’s “MSNBC Live with Thomas Roberts” line-up: Guest host Craig Melvin interviews former Unabomber profiler Candace DeLong, former ATF Agent in Charge James Cavanaugh and Rep. John Tierney (D-MA) about the bombings at the Boston Marathon…  Dr. Tad Gerlinger, MD, who treated wounded warriors in combat, will discuss how battlefield injuries can be applied to incidents like the Boston attack…  Rep. Luis Giutierrez will talk about whether poison pills will kill the Immigration 8 bipartisan compromise…  And MSNBC’s Martin Bashir will join from London to discuss Margaret Thatcher’s funeral and London on guard in the wake of the Boston attack.

*** Wednesday’s “Andrea Mitchell Reports” line-up: NBC’s Andrea Mitchell interviews Sen. Robert Menendez (D-NJ), former Homeland Security Secretary Tom Ridge, MSNBC’s Chris Jansing and Martin Bashir, NBC’s Pete Williams, Ron Allen, Kelly O’Donnell and Anne Thompson and The New York Times’ Mark Mazzetti.

*** Wednesday’s “News Nation with Tamron Hall” line-up: MSNBC’s Tamron Hall interviews Rep.  Raul Grijalva, USA Today columnist Raul Reyes, American Urban Radio’s April Ryan, and Professional Firefighters of MA president Edward Kelly