TnaA, an SP-RING Protein, Interacts with Osa, a Subunit of the Chromatin Remodeling Complex BRAHMA and with the SUMOylation Pathway in Drosophila melanogaster

Abstract

Tonalli A (TnaA) is a Drosophila melanogaster protein with an XSPRING domain. The XSPRING domain harbors an SP-RING zinc-finger, which is characteristic of proteins with SUMO E3 ligase activity. TnaA is required for homeotic gene expression and is presumably involved in the SUMOylation pathway. Here we analyzed some aspects of the TnaA location in embryo and larval stages and its genetic and biochemical interaction with SUMOylation pathway proteins. We describe that there are at least two TnaA proteins (TnaA130 and TnaA123) differentially expressed throughout development. We show that TnaA is chromatin-associated at discrete sites on polytene salivary gland chromosomes of third instar larvae and that tna mutant individuals do not survive to adulthood, with most dying as third instar larvae or pupae. The tna mutants that ultimately die as third instar larvae have an extended life span of at least 4 to 15 days as other SUMOylation pathway mutants. We show that TnaA physically interacts with the SUMO E2 conjugating enzyme Ubc9, and with the BRM complex subunit Osa. Furthermore, we show that tna and osa interact genetically with SUMOylation pathway components and individuals carrying mutations for these genes show a phenotype that can be the consequence of misexpression of developmental-related genes.

A comprehensive platform for the analysis of ubiquitin-like protein modifications using in vivo biotinylation

“…2B). Three of the validated proteins have been previously identified as SUMOylated proteins: Ultraspiracle (Usp), a nuclear receptor involved in steroid signalling46, the transcription factor Osa3747, the intermediate filament Lamin (Lam, also a key nuclear envelope component)38 and the eukaryotic initiation factor 4E (eIF-4E)48. One of the validated proteins was not previously described to be SUMOylated in Drosophila , the Glutathione S-transferase involved in axonogenesis Failed axon connections (Fax), and thus is the first Fax homolog to be identified as a target of SUMOylation.…”

Transcriptional Regulation by Trithorax-Group Proteins

“…Brd2/Ring3, a human counterpart of the Drosophila trxG gene fsh, encodes a nuclear protein kinase with two bromodomains, implicated in cell-cycle progression and leukemogenesis, but the substrates of the kinase are currently unknown (Denis and Green 1996). The trxG gene Tonalli (Tna) encodes a protein related to SP-RING finger proteins involved in sumoylation, suggesting that it may regulate transcription via the covalent modification of proteins other than histones (Gutierrez et al 2003;Monribot-Villanueva et al 2013). The trxG gene sallimus (sls) was identified in a screen for extragenic suppressors of Pc and subsequently found to encode Drosophila Titin (Machado and Andrew 2000).…”

Developmental transcriptional regulation by SUMOylation, an evolving field

“…Notably, two subunits of this module, Med12 and Med13 ( skuld and kohtalo respectively in Drosophila), were revealed both as trxG and PcG proteins in different genetic screenings designed to identify factors required to maintain the activation or the repression of Hox genes (Gaytán de Ayala et al, ; Kennison & Tamkun, ). So far, these two subunits have not been found SUMOylated in global analyses but they do interact genetically with TnaA, another trxG protein with a putative SUMO E3 ligase activity (see ahead) (Gutiérrez, Zurita, Kennison, & Vázquez, ; Monribot‐Villanueva et al, ).…”

“…In humans, the Brm‐related protein BRG1 (Hendriks & Vertegaal, ), and the Drosophila BAP subunit Osa (Monribot‐Villanueva et al, ; Nie et al, ) have been found SUMOylated. At least one Osa function could be to recruit the BAP complex to chromatin of genes that are going to be activated (Eroglu et al, ; Vázquez, Moore, & Kennison, ).…”

“…Further analyses showed that besides its interaction with brm , tna interacts even stronger with osa , the gene that encodes the Osa protein. Molecular characterization revealed that tna encodes TnaA, a protein with a domain characteristic of a class of E3 SUMO ligases (Gutiérrez et al, ; Monribot‐Villanueva et al, ) (see ahead).…”