DNA system provided the first clear suggestion that DNA carries genetic information. In 1933, while studying virgin sea urchin eggs, Jean Brachet suggested that DNA is found in the cell nucleus and that RNA is present exclusively in the cytoplasm. At the time, "yeast nucleic acid" (RNA) was thought to occur only in plants, while "thymus nucleic acid" (DNA) only in animals. The latter was thought to be a tetramer, with the function of buffering cellular pH. In 1937, William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure. In 1943, Oswald Avery, along with
Calcium signaling in cell division cell lines, that the G2/M checkpoint is regulated by CaMKII and MAPK crosstalk. Here, CaMKII activates MEK/ERK, which degrades the cell cycle arresting p27 protein In general, transformed cells proliferate in a calcium-independent manner, whereas non-transformed cells show high sensitivity to extra-cellular calcium concentration, suggesting oncogenic growth may include disruption of calcium signaling. Condensation of chromatin is a vital step in cell division, allowing cells to equally distribute chromosomes to the daughter cells. Recent work has suggested that Ca is required for enabling chromatin condensation in prometaphase. Calcium was found to concentrate on condensed DNA to much higher levels compared