Disease relevance of HIST1H1T

• The strains H1T, H3M and B1M could be identified as Desulfovibrio indonesiensis, and strain B2T as Desulfotomaculum geothermicum [1].

High impact information on HIST1H1T

• Nuclear condensation during spermiogenesis is accomplished by replacing somatic histones (linker histone H1 and core histones) and the testis-specific linker histone, H1t, with transition proteins and protamines [2].
• In addition to H1t, this novel H3 gene, which is located on chromosome 1, is the second tissue-specific human histone gene that has been found to be expressed solely in the testis [3].
• When Gln-54 in Histone H1t was mutated to lysine, its binding affinity towards DNA substrates was comparable to that of histone H1d [4].
• The glutamine residue in histone H1t forms a hydrogen bond with main chain carbonyl of methionine-52 (in H1t) and is spatially oriented away from the nucleosome dyad axis [4].
• A comparison of the globular domain sequences of the somatic H1d and testis-specific H1t revealed a single substitution of lysine 52 in H1d to glutamine 54 in H1t, which is one of the three crucial residues within the second DNA binding site [4].

Biological context of HIST1H1T

• Our study demonstrates, for the first time, the sequential expression of the testis-specific histone (H1t) and the transition proteins (TP1 and TP2) during normal human spermatogenesis [5].
• We have previously located the genes of the five human main type H1 genes and the gene encoding the testicular subtype H1t to the region 21.1 to 22.2 on the short arm of chromosome 6 [6].
• The gene coding for the human H1t histone, a testis-specific H1 subtype, was isolated from a genomic library using a human somatic H1 gene as a hybridization probe [7].
• Sequence analysis and S1 nuclease mapping of the human H1t gene reveals that the 5' flanking region contains several consensus promoter elements, as described for somatic, i.e., S-phase-dependent H1 subtype genes [7].
• However, other RFX family members have the same DNA-binding domain and they also may regulate H1t gene expression [8].

Anatomical context of HIST1H1T

• H1t mRNA could only be detected in the cytoplasm of mid and late pachytene spermatocytes [5].
• Concomitant with the onset of H1t transcription, the H1t protein appeared in the nuclei of pachytene spermatocytes and remain as a nuclear protein constituent up to step 5 spermatids [5].
• These data support the hypothesis that RFX2 expression is upregulated in spermatocytes where it participates in activating transcription of the H1t gene and other testis genes [8].
• The testicularly expressed histone genes H1t, Th2a and Th2b could be assigned to rat chromosome (RNO) 17 by PCR analysis of somatic cell hybrid DNAs [9].
• Complexes of histone H1 from sea urchin sperm (H1S) and calf thymus (H1T) with superhelical DNA I and relaxed circular DNA II have been analyzed by analytical sedimentation [10].

Associations of HIST1H1T with chemical compounds

• Three of them were obtained with methanol (strains H1M, H3M, and B1M), three strains with triethylene glycol (strains H1T, B1T, and B2T) and one strain with a mixture of lactate, acetate and butyrate (strain H1-13) [1].

Other interactions of HIST1H1T

• These spermatids were devoid of both CREM and TP1 but did contain H1t [11].
• Round spermatids show normal testis-specific H1t but reduced cAMP-responsive element modulator and transition protein 1 expression in men with round-spermatid maturation arrest [11].
• Antibodies against RFX2 generate a shifted band in electrophoretic mobility shift assays (EMSA) using H1t or testisin X-box DNA probes with nuclear proteins from spermatocytes [8].
• RFX2 levels decrease but RFX1 levels increase in early spermatids where H1t gene transcription is downregulated [8].
• Transcription factor RFX2 is abundant in rat testis and enriched in nuclei of primary spermatocytes where it appears to be required for transcription of the testis-specific histone H1t gene [8].

Analytical, diagnostic and therapeutic context of HIST1H1T

• Using the H1t X-box as an affinity chromatography probe, we identified Regulatory Factor X2 (RFX2), a member of the RFX family of transcription factors, as a nuclear protein that binds the probe [8].
• To identify the signaling pathway molecules that maintain the proliferation of hESCs, we performed a microarray analysis comparing an aneuploid H1 hESC line (named H1T) versus euploid H1 hESC line because the H1T hESC line demonstrates a self-renewal advantage while maintaining pluripotency [12].

References