Rapid histone extraction for electrophoretic analysis.

with 5% acetic acid and, after 10 min, the gel was finally washed in distilled water and air-dried onto the glass support. Air-drying allows the long and thin gel to be easily submitted to photographic and/or digital recording using a sequencing gel-sized scanner, such as the HP ScanJet 4C/T (Hewlett-Packard, Palo Alto, CA, USA). This avoids wethandling or the need of an apparatus for gel-drying between cellophane sheets. Once examined and/or recorded, the dried gel can be detached from the glass plate after overnight rinsing with warm 5 mol/L NaOH and the latter reused after extensive washing with detergent, ethanol and distilled water. In our laboratory, we have applied the full-length electrophoresis technique several times to the study of the pattern of proteins synthesized by MDA-MB231 tumor cells in response to microenvironmental stimuli (data not reported). Figure 1 shows that the protein gels submitted to full-length electrophoresis exhibit a sensitive staining of protein bands (from 30–60, depending on acrylamide concentration) and a low level of background, which make them suitable for documentation and for software-assisted qualitative and quantitative analysis of the electrophoretic pattern. The number of resolved proteins cannot be compared to that obtained by 2-D electrophoresis (see the 2-D protein map from MDA-MB231 cells available online at http://www.anl.gov/BIO/PMG/ projects/index_hbreast.html). Nevertheless, full-length 1-D electrophoresis is a faster method that (i) does not require special consumables and expensive apparatus (such as ampholytes and IPG gel systems), (ii) improves the resolution of the pattern of polypeptides submitted to monodimensional electrophoresis and (iii) expands the applications of the DNA sequencing apparatus for protein studies.