Linker histone H1 is present in centromeric chromatin of living human cells next to inner kinetochore proteins

The vertebrate kinetochore complex assembles at the centromere on α-satellite DNA. In humans, α-satellite DNA has a repeat length of 171 bp slightly longer than the DNA in the chromatosome containing the linker histone H1. The centromere-binding protein CENP-B binds specifically to α-satellite DNA with properties of a centromeric-linker histone. Here, we analysed if linker histone H1 is present at or excluded from centromeric chromatin by CENP-B. By immunostaining we detected the presence, but no enrichment or depletion of five different H1 subtypes at centromeric chromatin. The binding dynamics of H1 at centromeric sites were similar to that at other locations in the genome. These dynamics did not change in CENP-B depleted cells, suggesting that CENP-B and H1 co-exist in centromeric chromatin with no or little functional overlap. By bimolecular fluorescence complementation (BiFC) and Förster resonance energy transfer (FRET), we revealed that the linker histone H1 subtypes H1° and H1.2 bind to centromeric chromatin in interphase nuclei in direct neighbourhood to inner kinetochore proteins

Prognostic relevance of Centromere protein H expression in esophageal carcinoma

<p>Abstract</p> <p>Background</p> <p>Many kinetochore proteins have been shown to be associated with human cancers. The aim of the present study was to clarify the expression of Centromere protein H (CENP-H), one of the fundamental components of the human active kinetochore, in esophageal carcinoma and its correlation with clinicopathological features.</p> <p>Methods</p> <p>We examined the expression of CENP-H in immortalized esophageal epithelial cells as well as in esophageal carcinoma cells, and in 12 cases of esophageal carcinoma tissues and the paired normal esophageal tissues by RT-PCR and Western blot analysis. In addition, we analyzed CENP-H protein expression in 177 clinicopathologically characterized esophageal carcinoma cases by immunohistochemistry. Statistical analyses were applied to test for prognostic and diagnostic associations.</p> <p>Results</p> <p>The level of CENP-H mRNA and protein were higher in the immortalized cells, cancer cell lines and most cancer tissues than in normal control tissues. Immunohistochemistry showed that CENP-H was expressed in 127 of 171 ESCC cases (74.3%) and in 3 of 6 esophageal adenocarcinoma cases (50%). Statistical analysis of ESCC cases showed that there was a significant difference of CENP-H expression in patients categorized according to gender (<it>P </it>= 0.013), stage (<it>P </it>= 0.023) and T classification (<it>P </it>= 0.019). Patients with lower CENP-H expression had longer overall survival time than those with higher CENP-H expression. Multivariate analysis suggested that CENP-H expression was an independent prognostic marker for esophageal carcinoma patients. A prognostic value of CENP-H was also found in the subgroup of T3~T4 and N0 tumor classification.</p> <p>Conclusion</p> <p>Our results suggest that CENP-H protein is a valuable marker of esophageal carcinoma progression. CENP-H might be used as a valuable prognostic marker for esophageal carcinoma patients.</p

Linker histone H1 is present in centromeric

chromatin of living human cells next to inner kinetochore protein