[The Effect of the Knockout of Major Transsulfuration Genes on the Pattern of Protein Synthesis in D. melanogaster]

The enzymes involved in the transsulfuration pathway and hydrogen sulfide production-cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) - play an important cytoprotective role in the functioning of the organism. Using CRISPER/Cas9 technology, we obtained Drosophila strains with deleted cbs, cse, and mst genes as well as with double deletion of cbs and cse genes. We analyzed the effect of these mutations on the pattern of protein synthesis in the salivary glands of third instar larvae and in the ovaries of mature flies. In the salivary glands of strains with cbs and cse deletions, a decrease was found in the accumulation of the FBP2 storage protein containing 20% methionine amino acid residues. In the ovaries, changes were detected in the level of expression and isofocusing points of proteins involved in cell protection against oxidative stress, hypoxia, and protein degradation. It was shown that in the strains with deletions of transsulfuration enzymes the proteins have a similar degree of oxidation to that of the control strain. A decrease in the total number of proteasomes and their activity was found in the strains with deletions of the cbs and cse genes.

Deletions of the cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) genes, involved in the control of hydrogen sulfide biosynthesis, significantly affect lifespan and fitness components of Drosophila melanogaster

The gasotransmitter hydrogen sulfide (H₂S) is an important biological mediator, playing an essential role in many physiological and pathological processes. It is produced by transsulfuration - an evolutionarily highly conserved pathway for the metabolism of sulfur-containing amino acids methionine and cysteine. Cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) enzymes play a central role in cysteine metabolism and H₂S production. Here we investigated the fitness components (longevity, stress resistance, viability of preimaginal stages, and reproductive function parameters) in D. melanogaster lines containing deletions of the CBS and CSE genes. Surprisingly, in most tests, CSE deletion improved, and CBS worsened the fitness. Lines with deletion of both CBS and CSE demonstrated better stress resistance and longevity than lines with single CBS deletion. At the same time, deletion of both CBS and CSE genes causes more serious disturbances of reproductive function parameters than single CBS deletion. Thus, a complex interaction of H₂S-producing pathways and cellular stress response in determining the lifespan and fitness components of the whole organism was revealed.