Guppies (Poecilia reticulata) are colorful fish that have attracted the attention of pigmentation researchers for almost a century. Here, we report that the blond phenotype of the guppy is caused by a spontaneous mutation in the guppy ortholog of adenylate cyclase 5 (adcy5). Using double digest restriction site-associated DNA sequencing (ddRADseq) and quantitative trait locus (QTL) mapping, we linked the blond phenotype to a candidate region of 118 kb, in which we subsequently identified a 2-bp deletion in adcy5 that alters splicing and leads to a premature stop codon. We show that adcy5, which affects lifespan and melanoma growth in mouse, is required for melanophore development and formation of male orange pigmentation traits in the guppy. We find that some components of the male orange pattern are particularly sensitive to loss of Adcy5 function. Our work thus reveals a function for Adcy5 in patterning of fish color ornaments.
The THO/TREX complex mediates the transport of nascent mRNAs from the nucleus towards the cytoplasm in animals, and it has a role in small interfering RNA-dependent processes in plants. Here we describe five mutant alleles of Arabidopsis thaliana THO2, a core subunit of the plant THO/TREX complex. tho2 mutants present strong developmental defects resembling those in plants compromised in microRNA (miRNA) activity. In agreement, not only the levels of siRNAs, but also of mature miRNAs were reduced in tho2 mutants. As a consequence a feedback mechanism is triggered, increasing the amount of miRNA precursors, finally causing accumulation of miRNA-targeted mRNAs. Yeast two hybrid experiments and confocal microscopy showed that THO2 does not seem to interact with any of the known miRNA biogenesis components, but rather with the splicing machinery, implying an indirect role of THO2 in small RNA biogenesis. Using a RIP approach we found that THO2 is able to interact with miRNA precursors and that tho2 mutants fail to recruit such precursors into the miRNA-processing complex, explaining the reduction in the miRNA production in this mutant background. We also detected alterations in the splicing pattern of genes encoding Serine/Arginine-Rich (SR) proteins in tho2 mutants, supporting a previously unappreciated role of the THO/TREX complex in alternative splicing.
Its title: 'Pigment cell organization and genetic analysis of color pattern formation in the guppy’
Read more about Markus' research here.
in Paris, France
Claude and Jorge speaking at ICAR
July 13, 2015
Cold Spring Harbor, USA
Detlef teaching at Plant Science Course in Cold Spring
in Vienna, Austria
Moisés giving a talk about historic Arabidopsis samples at SMBE2015
July 27 - 28
in Knoxwille, USA
Derek will speak at the Workshop for Computational Advances in Microbiome Research (CAMR)