H1f8, also known as H1foo, is an oocyte-specific linker histone. Linker histones are involved in higher-order chromatin structure, and H1foo likely plays a key role in the control of gene expression during oogenesis and early embryogenesis, presumably through perturbing chromatin structure [3,4].

In mouse models, H1foo knockdown in one-cell-stage embryos causes the chromatin structure in the pronucleus to be tighter and increases deposition of histone H3 variant H3.1/3.2 in the peripheral region of the pronucleus. Overexpressing H1foo leads to less decrease in chromatin looseness at the two-cell stage, suggesting its involvement in the change of chromatin structure via nuclear deposition of H3 variants between the one-and two-cell stages [1]. Also, in H1foo-overexpressing mouse embryonic stem cells, H1foo is enriched around the transcriptional start sites of genes like oocyte-specific genes, relaxing the chromatin structures at these regions. It physiologically binds to Esrrb, and Esrrb is necessary for H1foo-mediated chromatin decondensation at target loci [2].

In summary, H1f8 (H1foo) is crucial for regulating chromatin structure during early embryonic development. Studies using mouse models have revealed its role in processes such as chromatin condensation and decondensation, and its interaction with other factors like Esrrb. Understanding H1f8 may provide insights into early embryonic development and potentially related disorders [1,2].

References:

1. Funaya, Satoshi, Ooga, Masatoshi, Suzuki, Masataka G, Aoki, Fugaku. 2018. Linker histone H1FOO regulates the chromatin structure in mouse zygotes. In FEBS letters, 592, 2414-2424. doi:10.1002/1873-3468.13175. https://pubmed.ncbi.nlm.nih.gov/29963710/

2. Hayakawa, Koji, Tanaka, Satoshi. 2021. Oocyte-specific linker histone H1foo interacts with Esrrb to induce chromatin decondensation at specific gene loci. In Biochemical and biophysical research communications, 561, 165-171. doi:10.1016/j.bbrc.2021.05.033. https://pubmed.ncbi.nlm.nih.gov/34023782/

3. Tanaka, Mamoru, Kihara, Maki, Meczekalski, Blazej, King, Gretchen J, Adashi, Eli Y. . H1oo: a pre-embryonic H1 linker histone in search of a function. In Molecular and cellular endocrinology, 202, 5-9. doi:. https://pubmed.ncbi.nlm.nih.gov/12770723/

4. Tanaka, M, Hennebold, J D, Macfarlane, J, Adashi, E Y. . A mammalian oocyte-specific linker histone gene H1oo: homology with the genes for the oocyte-specific cleavage stage histone (cs-H1) of sea urchin and the B4/H1M histone of the frog. In Development (Cambridge, England), 128, 655-64. doi:. https://pubmed.ncbi.nlm.nih.gov/11171391/