Varied Expression Patterns of Human H1 Histone Genes in Different Cell Lines

Abstract

Five main type H1 histones have been described in man (H1.1-H1.5) in addition to the testis specific type H1t and the replacement subtype H1 degrees, which is found mainly in highly differentiated cells. We have isolated this whole complement of H1 genes and have studied the expression of the seven human H1 subtype genes in several cell lines. The RNAase protection assay was used to discriminate between the very similar transcripts derived from the seven H1 subtype genes. With the exception of H1.2 and H1.4, we found substantial differences between the H1 mRNA levels in the different cell lines tested. No H1.1 mRNA was detected in most of the cell lines and just a low level of H1.1 mRNA was found in human testis. In contrast to the differential patterns of the other subtypes, H1.2 and H1.4 were in all cells expressed at a high level, indicating a basal function compared with the other H1 histones. Because differences in the timing of H1 protein subtype synthesis have been reported, we have analyzed the kinetics of accumulation of H1 subtypes in synchronized HeLa cells and observed that all H1 subtypes examined (H1 degrees, H1.2-H1.5) were expressed in a replication-dependent manner. The analysis showed a differential rise of mRNA levels during S-phase, from four-fold (H1 degrees) to 15-fold (H1.5). Our results may point at a specific function of each subtype and suggest that expression of the H1 histone subtype genes depends on common S-phase-depent factors as well as on individual regulatory systems. Thus, the data presented here provide a basis for further analysis of the regulation and function of the complex H1 gene and protein family.

Conserved sequence elements in human main type‐H1 histone gene promoters : their role in H1 gene expression

“…For analysis of cell-cycle-dependent promoter elements, aphidicolin was used to block transfected cells at the transition from the G1 phase to the S phase of the cell cycle [19]). After transfection of four cultures with the identical individual luciferase-promotor construct, as described above, cells were blocked with aphidicolin (final concentration 15 µM) for 24 h. After this blocking, two of the four cultures transfected in parallel were released from the S-phase block by replacing the aphidicolin-containing medium, whereas the other two cultures remained under blocking conditions.…”

“…Varied patterns of H1 subtype proteins have been documented in different mouse tissues, depending on the state of development or differentiation [17,18]. Similarly, differential expression patterns of the human H1 histone genes have been observed on comparison of mRNA levels in different human cell lines [19]). This differential expression points towards a functional relevance of the individual H1 subtypes.…”

“…First, the differential expression patterns of H1-subtype genes in different cell types may require subtype-specific mechanisms of regulation. Second, since the mRNA of all main-type H1 genes accumulates during the S phase of the cell cycle [19], common control elements may be involved in H1 gene activation on entry into the S phase.…”

A dual role of linker histone H1.4 Lys 34 acetylation in transcriptional activation

“…We chose the human linker histone subtype H1.4 as a model, as it is highly abundant, widely expressed (Lennox and Cohen 1983;Meergans et al 1997), and the most conserved human linker histone subtype (Supplemental Fig. S1A).…”

Global Changes in and Characterization of Specific Sites of Phosphorylation in Mouse and Human Histone H1 Isoforms upon CDK Inhibitor Treatment Using Mass Spectrometry

“…This is not unexpected, as it had been previously reported that in cells in culture and in mammalian tissue, the H1.2 and H1.4 isoforms are more broadly expressed in all cell types, whereas expression of other H1 isoforms are often down-regulated in differentiated cells. 27,28 To determine the phosphorylation status of these human H1 isoforms, the two HPLC fractions were analyzed by electrospray mass spectrometry and the data are summarized in Table 1. The ESI/MS analyses of the first HPLC peak show ions which correspond in mass to the unmodified H1.0 isoform.…”