Disease relevance of BEAF-32

• Expression of BEAF32A also induced extensive apoptosis of eye imaginal disc cells and, consistent with this, co-expression of baculovirus P35 in the eye imaginal disc suppressed the BEAF32A-induced rough eye phenotype [1].

High impact information on BEAF-32

• Their palindromic binding sites (CGATA-TATCG) symmetrically abut the previously mapped hypersensitive site of scs'. We have cloned a cDNA for one of these proteins, BEAF-32 (boundary element-associated factor of 32 kDa) [2].
• Immunostaining localizes BEAF to hundreds of interbands and many puff boundaries on polytene chromosomes, suggesting that a chromosomal domain consists of a band (or puff) and part of the flanking interbands [2].
• We show that the Drosophila scs and scs' boundary proteins, Zw5 and BEAF, respectively, interact with each other in vitro and in vivo [3].
• The Drosophila boundary protein BEAF and, unexpectedly, the mammalian factor Sp1 exhibited a robust BA in yeast [4].
• Taken together, these findings suggest that clustered CGATA motifs are a hallmark of a BEAF-utilizing class of boundary elements found at many loci [5].

Biological context of BEAF-32

• The boundary element-associated factor BEAF is one protein that is implicated in boundary element function [6].
• This sequence contains a BEAF-binding sequence juxtaposed to an AT-rich sequence that harbors a strong nuclease-hypersensitive site [7].
• DREF is believed to regulate genes whose products are involved in DNA replication and cell proliferation, suggesting that the activation of transcription predicted to result from the displacement of BEAF by DREF might be limited to certain rapidly proliferating tissues [6].
• BEAF-32 is a protein present in the scs' element of Drosophila that is also localized to most interband regions and puffs of polytene chromosomes, suggesting a role in the organization of structural chromosomal domains [8].
• Furthermore, point mutations in CGATA motifs that eliminate binding by BEAF also eliminate the ability to confer position-independent expression [5].

Anatomical context of BEAF-32

• In the developing eye imaginal disc, expression of BEAF32A inhibited differentiation of photoreceptor cells [1].
• Expression of BID in salivary glands leads to a global disruption of polytene chromatin structure, and this disruption is largely rescued by an extra copy of BEAF [9].

Other interactions of BEAF-32

• To our knowledge, this is the first evidence for a genetic interaction between DREF and BEAF-32 [10].
• We propose that the BE28 repeat clusters could fulfill a similar function, acting as a local boundary between hetero- and euchromatin in a process involving interactions between the BEAF and D1 proteins [7].
• Four proteins have been identified in Drosophila mediating enhancer blocking-Su(Hw), Zw5, BEAF32 and GAGA factor [11].

Analytical, diagnostic and therapeutic context of BEAF-32

• To investigate the effects of BEAF32A on regulation of chromatin structure, genetic crosses of the BEAF32A-overexpressing flies with loss-of-function mutants for genes encoding other boundary element-binding factors or regulators of chromatin structure were conducted [1].

References