RT Journal Article
SR Electronic
T1 Uncultured marine cyanophages encode for active NblA, phycobilisome proteolysis adaptor protein
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 494369
DO 10.1101/494369
A1 Omer Nadel
A1 Andrey Rozenberg
A1 José Flores-Uribe
A1 Shirley Larom
A1 Rakefet Schwarz
A1 Oded Béjà
YR 2018
UL http://biorxiv.org/content/early/2018/12/13/494369.1.abstract
AB Phycobilisomes (PBS) are large water-soluble membrane-associated complexes in cyanobacteria and some chloroplasts that serve as a light-harvesting antennas for the photosynthetic apparatus. When short of nitrogen or sulfur, cyanobacteria readily degrade their phycobilisomes allowing the cell to replenish the vanishing nutrients. The key regulator in the degradation process is NblA, a small protein (~6 kDa) which recruits proteases to the PBS. It was discovered previously that not only do cyanobacteria possess nblA genes but also that they are encoded by genomes of some freshwater cyanophages. A recent study, using assemblies from oceanic metagenomes, revealed genomes of a novel uncultured marine cyanophage lineage which contain genes coding for the PBS degradation protein. Here, we examine the functionality of nblA-like genes from these marine cyanophages by testing them in a freshwater model cyanobacterial nblA knockout. One of the viral NblA variants could complement the non-bleaching phenotype and restore PBS degradation. Our findings reveal a functional NblA from a novel marine cyanophage lineage. Furthermore, we shed new light on the distribution of nblA genes in cyanobacteria and cyanophages.Originality-Significance Statement This is the first study to examine the distribution and function of nblA genes of marine cyanophage origin. We describe as well the distribution of nblA-like genes in marine cyanobacteria using bioinformatic methods.