Figure 4.

Electron micrographs (low magnification) of filaments formed by dialysis of A2 and B1 preparations against 0.1× STMM buffer. Initial protein concentrations were near 0.1 mg/ml (A) and 0.2 mg/ml (B). Bars, 500 nm. Note increasing filament anastomosis, aggregation, and globular particle formation at higher protein concentrations. (C) Salt-insoluble material formed upon RNase digestion of concentrated 40S hnRNP particle preparations in 0.1× STMM buffer. The thinner fibers in A are 7–10 nm in diameter. At higher protein concentration most fibers fall in the diameter range of 10–20 nm. Bar 100 nm.