title: The alternative protein isoform NK2B, encoded by the vnd/NK-2 proneural gene, directly activates transcription and is expressed following the start of cells differentiation.
abstract: NK-2 is a homeodomain protein essential for the development of the central nervous system in the Drosophila embryo. Here, we show that the vnd/NK-2 gene encodes an additional protein isoform (NK-2B) that differs from the known one (NK-2A) in its N-terminal domain. While NK-2A is a transcription repressor, NK-2B directly activates transcription from promoters containing NK-2 binding sites, with its N-terminal domain possessing a strong transcription activation potency. The transcription of NK-2B starts at the onset of metamorphosis. Its expression is observed in precursors of differentiating photoreceptors and in photoreceptors of the adult eye. Both NK-2B and NK-2A are expressed in the lamina. However, the expression of NK-2A is mostly associated with the undifferentiated state of nervous cells.
authors.affiliation: Department of Transcription Factors, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova Street 32, Moscow, 119991 Russia. sstepalex@mail.ru
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Stepchenko
authors.forename: Elizaveta V
authors.initials: EV
authors.lastname: Pankratova
authors.forename: Semen A
authors.initials: SA
authors.lastname: Doronin
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Gulag
authors.forename: Sofia G
authors.initials: SG
authors.lastname: Georgieva
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002490:Central Nervous System / Q000254:growth & development / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development; D005091:Exons; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D020033:Protein Isoforms; D015534:Trans-Activators; D014157:Transcription Factors; C094797:vnd protein, Drosophila