Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

A house of cards? Sounds unbelievable, doesn't it? Not if the architect is 31-year-old Bryan Berg. He's made a career out of building fantastic card houses, stadiums, capitols, castles -- and the world's tallest card tower. How does he do it? Bryan's structures are amazing because they are made entirely of perfectly balanced, freestanding playing cards. He never uses glue, tape, or anything else to hold the cards together. Nor does he fold the cards. He's discovered another way to make a strong house of cards, using a trick from nature. To make plants strong, nature builds them with cells that have tough walls. Rows and rows of these cells form a grid that helps leaves and stems keep their shape. Bees use the same kind of repeating pattern to create strong honeycombs, where they live and store honey. Bryan designs similar grids, using cards to create a repeating pattern of cells. He begins with a single cell made by balancing four cards against one another to form a box. Then he repeats the cell over and over, expanding outward to form the grid, which makes a good foundation for a strong card structure. The larger the grid, the more weight it can carry. Sometimes Bryan uses several cards, instead of just one, to construct the cell walls, making the grid even stronger. The trick, he tells kids when he speaks in classrooms, is to place your cards as tightly together as possible when laying out your grid, making sure the cards are not leaning at all. After building this solid base, Bryan lays cards across the top to make the floor for the next "story" of the building. He may add towers, columns, steeples, or domes. Using the principle of repeating cells, Bryan builds structures of amazing strength. In the Cards Not surprisingly, Bryan has always been interested in building things. Growing up on a "big, old farm" in rural Iowa, he had plenty of room to play. "We were in the middle of nowhere," Bryan remembers, "with lots of space to do whatever we wanted. I was always making something, using things like sticks or bales of hay." Bryan's grandfather taught him how to stack cards. Bryan's two interests -- building and card stacking -- soon combined. But stacking in his family's farmhouse was challenging. "Our old house had wood floors that weren't all level," he reports. "And they weren't very firm. When people walked around, it was like 'earthquake action.' It was a challenge to build something that wouldn't fall down immediately." Bryan constructed tower after tower; he went through a lot of trial and error before he built anything taller than himself. When he placed a few decks of cards on top of his grid, he discovered how strong it was. Bryan's towers began to grow taller. How Tall Is Too Tall? Bryan's first Guinness World Record for the world's tallest card tower came in the spring of 1992, when he was in high school. Learning that the world record was 12 feet 10 inches, Bryan built a slim tower that topped out at 14 feet 6 inches. Done as a project for his geometry class, it took him 40 hours and 208 decks of cards. Since then he's gone on to win world records for even taller buildings. His latest winner measured 25 feet 3.5 inches and used about 2,400 decks of cards. _ Why don't these towers fall down? The key is in a good solid base, a repeating pattern of stories, and a tapering top. Bryan likes to point out how card buildings resemble real ones. They are built cell by cell, story by story. The separate parts make one strong whole. The heavier the building, the stronger and more stable it is. But the weight can't all be at the top. After spending so much time building something so cool, Bryan admits it's sometimes painful to see his structures destroyed. But he compares his work to the building of a sandcastle or an ice sculpture.
What was Bryan's first world record?

MicroRNAs (miRNAs) constitute a large family of noncoding RNAs that function as guide molecules in diverse gene silencing pathways. Current efforts are focused on the regulatory function of miRNAs, while little is known about how these unusual genes themselves are regulated. Here we present the first direct evidence that miRNA genes are transcribed by RNA polymerase II (pol II). The primary miRNA transcripts (pri-miRNAs) contain cap structures as well as poly(A) tails, which are the unique properties of class II gene transcripts. The treatment of human cells with alpha-amanitin decreased the level of pri-miRNAs at a concentration that selectively inhibits pol II activity. Furthermore, chromatin immunoprecipitation analyses show that pol II is physically associated with a miRNA promoter. We also describe, for the first time, the detailed structure of a miRNA gene by determining the promoter and the terminator of mir-23a approximately 27a approximately 24-2. These data indicate that pol II is the main, if not the only, RNA polymerase for miRNA gene transcription. Our study offers a basis for understanding the structure and regulation of miRNA genes.
Which polymerase transcribes pri-miRNAs?

Lewy bodies, neuropathological hallmarks of Parkinson's disease and dementia with Lewy bodies, comprise alpha-synuclein filaments and other less defined proteins. Characterization of Lewy body proteins that interact with alpha-synuclein may provide insight into the mechanism of Lewy body formation. Double immunofluorescence labeling and confocal microscopy revealed approximately 80% of cortical Lewy bodies contained microtubule-associated protein 1B (MAP-1B) that overlapped with alpha-synuclein. Lewy bodies were isolated using an immunomagnetic technique from brain tissue of patients dying with dementia with Lewy bodies. Lewy body proteins were resolved by polyacrylamide gel electrophoresis. Immunoblotting confirmed the presence of MAP-1B and alpha-synuclein in purified Lewy bodies. Direct binding studies revealed a high affinity interaction (IC(50) approximately 20 nm) between MAP-1B and alpha-synuclein. The MAP-1B-binding sites were mapped to the last 45 amino acids of the alpha-synuclein C terminus. MAP-1B also bound in vitro assembled alpha-synuclein fibrils. Thus, MAP-1B may be involved in the pathogenesis of Lewy bodies via its interaction with monomeric and fibrillar alpha-synuclein.

Which is the primary protein component of Lewy bodies?