High impact information on Nap1

• In addition, acf1 genetically interacts with nap1, which encodes the NAP-1 nucleosome assembly protein [1].
• We suggest that late-replicating pericentric heterochromatin helps to maintain embedded centromeres by blocking conventional nucleosome assembly early in S phase, thereby allowing the deposition of centromeric histones [2].
• Chromatin associated with transcriptionally active loci becomes enriched for histones with particular lysine modifications and accumulates the H3.3 histone variant, the substrate for replication-independent nucleosome assembly [3].
• Increasing the duration of nucleosome assembly progressively inactivated a plasmid template when it was transcribed with extracts of either unshocked or heat-shocked Drosophila embryos, despite induction of the transcriptional activator heat shock factor [4].
• Dual roles of p300 in chromatin assembly and transcriptional activation in cooperation with nucleosome assembly protein 1 in vitro [5].

Biological context of Nap1

• We conclude that this example of gene targeting at the Nap1 locus provides added support for the efficiency of this method and its usefulness in targeting any arbitrary locus in the Drosophila genome [6].
• Thus, NAP-1 appears to be one component of a multifactor chromatin assembly machinery that mediates the ATP-facilitated assembly of regularly spaced nucleosomal arrays [7].
• Studies of the localization of dNAP-1 in the Drosophila embryo revealed that the factor is present in the nucleus during S phase and is predominantly cytoplasmic during G2 phase [7].
• With ACF + dNAP1-assembled chromatin, we found that transcriptional activation is dependent upon acetyl-CoA [8].
• The recombinant histones were efficiently assembled into periodic nucleosome arrays in a completely purified recombinant system with Drosophila ATP-utilizing chromatin assembly and remodeling factor (ACF), Drosophila nucleosome assembly protein-1, plasmid DNA, and ATP [9].

Anatomical context of Nap1

• The nucleosome assembly protein-1 (NAP1) was originally identified in HeLa cells as a factor facilitating the in vitro assembly of nucleosomes [10].

Associations of Nap1 with chemical compounds

• Transcriptional analysis of chromatin assembled with purified ACF and dNAP1 reveals that acetyl-CoA is required for preinitiation complex assembly [8].
• Substitution of the identified phosphoresidues by alanine was found to reduce considerably the ability of CK2 to phosphorylate NAP1 [10].
• Thus, the H1 histone, polylysine and spermine facilitate nucleosome assembly in vitro [11].
• H1 histone, polylysine and spermine facilitate nucleosome assembly in vitro [11].

Physical interactions of Nap1

• These and other data collectively suggest that dNLP may participate in parallel with other histone-binding proteins such as dNAP-1 in the assembly of chromatin [12].
• HMG-D interacts with DNA during the early phases of nucleosome assembly but is gradually displaced as chromatin matures [13].

Enzymatic interactions of Nap1

• CHD1 catalyzes the ATP-dependent transfer of histones from the NAP1 chaperone to the DNA by a processive mechanism that yields regularly spaced nucleosomes [14].

Other interactions of Nap1

• We observed that dNAP-1, but not dNLP, was able to promote the decondensation of sperm chromatin [12].
• Purified, recombinant dNAP-1 acts cooperatively with a factor(s) in the dCAF-1 fraction in the efficient and DNA replication-independent assembly of chromatin [7].
• H2AvD is therefore both essential and continuously present, suggesting a requirement for its utilization, either to provide an alternative capability for nucleosome assembly or to generate an alternative nucleosome structure [15].
• Chromatin assembly in vitro with purified recombinant ACF and NAP-1 [16].
• This reaction involves purified CHD1, NAP1 chaperone, core histones and relaxed DNA [14].

References