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. Author manuscript; available in PMC: 2012 Aug 1.
Published in final edited form as: Dev Biol. 2011 May 11;356(1):19–27. doi: 10.1016/j.ydbio.2011.05.004

Figure 4.

Figure 4

Morphogenetic activity of heparin and de2OS and de6OS column fractions. Phase contrast photomicrographs of isolated ureteric buds (UB) cultured in either whole BSN-CM (a), DMEM/F12 (b) or purified fractions eluted from the columns (c-t). Isolated UBs cultured in whole BSN-CM (a, positive control) are large and have distinct stalks and tips while UBs cultured in DMEM/F12 alone (b, negative control) display little growth or branching. Isolated UBs cultured in purified fractions of BSN-CM run over the heparin column (c-h), 2OS-depleted heparin column (i-n) or 6OS-depleted heparin column (o-t) demonstrate the presence of branch and growth promoting factors. The elution profiles demonstrate a progressive downward shift of binding affinity of stimulatory activity suggesting that HS 6-O sulfation is necessary for high affinity binding. Of note, robust branch stimulatory activity is detected in the flow-through fraction of the de6OS column (o), but not in the heparin (c) or de2OS (i) columns, indicating a lack of binding to the de6OS column despite the presence of other sulfation modifications.