Figure 4. Effect of Cytoplasm on H1M and Domain Truncation Mutants.

(A) Coomassie-stained gel of full-length (FL) H1M, amino-globular domains (ΔC), and C-terminal domain (ΔNG), with schematic of the proteins shown at right of the corresponding band. (B) Quantification of H1:DNA fluorescence intensity (average ± standard error) and (C) representative immunofluorescence images of sperm chromatin in buffer or extract supplemented with 1 µM H1M full-length or domains. In extract, full-length H1 localizes as efficiently as it does in buffer, while a sharp drop in localization intensity is observed for the domains. H1 was immunolocalized using the 6XHistidine tag (6XHis) common to all three constructs. For visualization purposes, DNA and H1 signal were brightened in the extract condition relative to buffer. Scale bar, 10 µm.