Disease relevance of Hel25E

• A recombinant RNA helicase A containing 6 histidine residues at the NH2 terminus was expressed in Sf9 cells using a baculovirus vector [1].
• One mus309 allele, which carries a stop codon between two of the helicase motifs, causes partial male sterility and complete female sterility [2].
• One ORF encodes a picornavirus-like cassette of proteins for virus replication, including an iflavirus-like RNA-dependent RNA polymerase and a helicase that is related to those of mammalian picornaviruses [3].
• The 5' ORF contains regions of similarities with the RNA-dependent RNA polymerase, helicase and protease domains of viruses from the picornavirus, comovirus and sequivirus families [4].

High impact information on Hel25E

• The mle(napts) RNA helicase mutation in drosophila results in a splicing catastrophe of the para Na+ channel transcript in a region of RNA editing [5].
• NXF1, p15 and UAP56 are essential nuclear mRNA export factors [6].
• SDE3 encodes an RNA helicase required for post-transcriptional gene silencing in Arabidopsis [7].
• These results indicate that the NTPase/helicase activities are essential functions of MLE for dosage compensation, perhaps utilized for chromatin remodeling of X-linked genes [8].
• Isolation of the Cdc45/Mcm2-7/GINS (CMG) complex, a candidate for the eukaryotic DNA replication fork helicase [9].

Biological context of Hel25E

• Our results also confirm that Sub2p affects heterochromatic gene expression, similar to that observed with the Drosophila Hel25E homologue [10].
• The deduced amino acid sequence from this clone showed that RNA helicase A is a member of the DEAH family of proteins thought to be helicases [1].
• A complementary DNA (cDNA) clone expressing RNA helicase A was isolated by screening a human cDNA library with polyclonal antibodies produced against the purified protein [1].
• The DExH/D box protein HEL/UAP56 is essential for mRNA nuclear export in Drosophila [11].
• HEL protein associates with salivary gland chromosomes and locates to nuclei of embryos and ovaries, but disappears in mitotic domains of embryos as chromosomes condense [12].

Anatomical context of Hel25E

• RNA helicase A is an abundant nuclear enzyme of HeLa cells that unwinds double-stranded RNA in a 3' to 5'direction (Lee, C. G., and Hurwitz, J. (1992) J. Biol. Chem. 267, 4398-4407) [1].
• The Sciara mle gene produces a single transcript, encoding a helicase, which is present in both male and female larvae and adults and in testes and ovaries [13].
• Our dominant negative analysis of d-mtDNA helicase in cultured cells provides a tractable model for understanding human autosomal dominant progressive external ophthalmoplegia mutations [14].
• In this study, we found that, in Xenopus pre-stage I and stage I oocytes, nuage and mitochondrial cement contain the spliceosomal Sm proteins, Xcat2 mRNA, and DEAD-box RNA helicase XVLG1 [15].
• In this study we sought to examine if the producers of blood platelets, megakaryocytic cells (using the cell lines MEG01, DAMI, HEL), expressed these genes [16].

Associations of Hel25E with chemical compounds

• While the vast majority of mRNAs were unaffected by LMB, the levels of most mRNAs were significantly reduced in cells depleted of NXF1, p15 or UAP56 [6].
• Mutation of a highly conserved lysine to methionine in helicase domain I eliminated both activities [17].

Regulatory relationships of Hel25E

• We propose that the HEL protein promotes an open chromatin structure that favors transcription during development by regulating the spread of heterochromatin, and that HEL is regulated by, and may have a role in, the mitotic cell cycle during embryogenesis [12].

Other interactions of Hel25E

• In many species examined, Vasa, a DEAD-box RNA helicase, is found in these morphologically distinct particles [18].
• Although the properties of factor 2 suggested that it might have helicase activity, we were unable to detect any DNA unwinding activity associated with factor 2 [19].
• Analysis of helicase activity and substrate specificity of Drosophila RECQ5 [20].
• The C-terminal portion of the Mus308 polypeptide encodes a DNA polymerase, whereas a putative DNA helicase is encoded by the N-terminal portion [17].
• In addition, the immunoprecipitated material has DNA-dependent ATPase but lacks detectable helicase [21].

Analytical, diagnostic and therapeutic context of Hel25E

• Here, we report on the molecular cloning and sequence determination of the complementary DNA (cDNA) coding for this DNA and RNA helicase [22].
• Partially degenerate oligonucleotides to two conserved amino acid sequences of this family were used to prime a polymerase chain reaction (PCR) amplification of HEL cell cDNA [23].

References