The nop-1 gene of Neurospora crassa encodes a seven transmembrane helix retinal-binding protein homologous to archaeal rhodopsins
AUTOR(ES)
Bieszke, Jennifer A.
FONTE
The National Academy of Sciences
RESUMO
Opsins are a class of retinal-binding, seven transmembrane helix proteins that function as light-responsive ion pumps or sensory receptors. Previously, genes encoding opsins had been identified in animals and the Archaea but not in fungi or other eukaryotic microorganisms. Here, we report the identification and mutational analysis of an opsin gene, nop-1, from the eukaryotic filamentous fungus Neurospora crassa. The nop-1 amino acid sequence predicts a protein that shares up to 81.8% amino acid identity with archaeal opsins in the 22 retinal binding pocket residues, including the conserved lysine residue that forms a Schiff base linkage with retinal. Evolutionary analysis revealed relatedness not only between NOP-1 and archaeal opsins but also between NOP-1 and several fungal opsin-related proteins that lack the Schiff base lysine residue. The results provide evidence for a eukaryotic opsin family homologous to the archaeal opsins, providing a plausible link between archaeal and visual opsins. Extensive analysis of Δnop-1 strains did not reveal obvious defects in light-regulated processes under normal laboratory conditions. However, results from Northern analysis support light and conidiation-based regulation of nop-1 gene expression, and NOP-1 protein heterologously expressed in Pichia pastoris is labeled by using all-trans [3H]retinal, suggesting that NOP-1 functions as a rhodopsin in N. crassa photobiology.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=22183Documentos Relacionados
- Isolation and characterization of the retinal-binding component of halorhodopsin
- nit-2, the major positive-acting nitrogen regulatory gene of Neurospora crassa, encodes a sequence-specific DNA-binding protein.
- cot-1, a gene required for hyphal elongation in Neurospora crassa, encodes a protein kinase.
- Isolation and characterization of a Neurospora crassa ribosomal protein gene homologous to CYH2 of yeast.
- The cross-pathway control gene of Neurospora crassa, cpc-1, encodes a protein similar to GCN4 of yeast and the DNA-binding domain of the oncogene v-jun-encoded protein.