Transgenic Drosophila melanogaster Carrying a Human Full-Length DISC1 Construct (UAS-hflDISC1) Showing Effects on Social Interaction Networks

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The current manuscript is an interesting study on the genetic modification of Drosophila melanogaster with a human full-length DISC1 construct, and its consequences on social interaction networks. Several relevant studies were performed, statistical analysis was well applied to the data, and relevant conclusions were drawn. Hence, I only advise on the following alterations before acceptance for publication:

- A final “conclusion” sentence is missing from the abstract;

- References seem to appear individually, for example as “[13], [14], [15], [16]”, when they should appear together as “[13 – 16]”, this should be corrected throughout the manuscript;

- The usefulness of Drosophila melanogaster as a model should be discussed in depth, namely its correlation to the human body, and consequent disparities and limitations, given that it is a fly;

- In the introduction section, an image should be created regarding DISC1 role in schizophrenia, including related symptoms, and molecular mechanisms, for better information summarization and reader understanding;

- The introduction section should “stop” at the study’s objectives, not including a summarization of the obtained results, these are meant for the following sections;

- In structural terms, an additional space should exist between subsections, they are currently too “joined together”;

- DISC1 should be commented as a potential therapeutic target, and novel therapeutical molecules that might be under development to target it should be mentioned and discussed; these relevant references can be used, among others:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5476421/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983783/

https://www.sciencedirect.com/science/article/pii/S1044743107002503

- An abbreviation list is missing and should be added.

Author Response

Reviewer 1

 

The current manuscript is an interesting study on the genetic modification of Drosophila melanogaster with a human full-length DISC1 construct, and its consequences on social interaction networks. Several relevant studies were performed, statistical analysis was well applied to the data, and relevant conclusions were drawn. Hence, I only advise on the following alterations before acceptance for publication:

1. A final “conclusion” sentence is missing from the abstract;

 

We thank the reviewer for his/her comments on our manuscript. We have added two separate conclusions, one from behavioral and one from biochemical measurements. The first is added in line 24-28 “The changes in social behavior and motor function suggest that the inserted hflDISC1 gene influences nervous system functioning that parallels symptoms of DISC1-related mental diseases in humans. Furthermore, neurochemical analyses of transgenic lines revealed increased levels of hydrogen peroxide and decreased levels of glutathione, indicating an impact of DISC1 on the dynamics of redox regulation, similar to one reported in mammals.“ And finally we gave an overall conclusion in lines 28-30 “Future studies are needed to address the localization of DISC1 expression and to address how the redox parameter changes correlate with the observed behavioral changes.”.

 

2. References seem to appear individually, for example as “[13], [14], [15], [16]”, when they should appear together as “[13 – 16]”, this should be corrected throughout the manuscript;

 

We thank the Review for the suggestion and have grouped references together as suggested.

 

3. The usefulness of Drosophila melanogaster as a model should be discussed in depth, namely its correlation to the human body, and consequent disparities and limitations, given that it is a fly;

 

We agree with the Reviewer about this, and indeed already include a paragraph on this topic, starting at line 106. To reinforce this, we have made changes and added sentences in lines 118-134 and lines 137-157. Furthermore we rephrased and now emphasized the value of Drosophila as a model organism in line 160-172.

 

4. In the introduction section, an image should be created regarding DISC1 role in schizophrenia, including related symptoms, and molecular mechanisms, for better information summarization and reader understanding;

 

This is a very good idea, and we now include such a diagram as new Figure 1.

 

5. The introduction section should “stop” at the study’s objectives, not including a summarization of the obtained results, these are meant for the following sections;

 

We agree with the Reviewer and we have revised the Introduction to ensure it focuses on setting up the background and objectives of the study without summarizing the results. The results are addressed in the appropriate sections that follow introduction.

6. In structural terms, an additional space should exist between subsections, they are currently too “joined together”;

 

As suggested, we have added additional spaces to improve the clarity and distinction between subsections.

 

7. DISC1 should be commented as a potential therapeutic target, and novel therapeutical molecules that might be under development to target it should be mentioned and discussed; these relevant references can be used, among others:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5476421/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983783/

https://www.sciencedirect.com/science/article/pii/S1044743107002503

We thank reviewer for a valuable information. We have added the references highlighting the therapeutic potential of DISC1 and its interacting proteins in treating neuropsychiatric disorders in line 723-726. The new references are numbers 64-66 in the reference list.

 

8. An abbreviation list is missing and should be added.

 

We thank reviewer for suggestion. While we appreciate the importance of an abbreviation list, we have opted to define abbreviations at their first mention in the text to maintain the flow and readability of the manuscript and we excluded abbreviations that are mentioned less than twice in the text. We believe this approach keeps the document concise and easy to follow, and is in accordance with the preferred style of the journal.

Reviewer 2 Report

Comments and Suggestions for Authors

Here are my comments and suggestions:

1. The introduction could be more concise and focused. There is a lot of background information provided, but it could be streamlined to more clearly set up the specific aims and hypotheses of this study.
2. The methods section is quite detailed, but could benefit from some reorganization. Grouping related methods together (e.g. all behavioral assays, all biochemical assays) may improve readability.
3. The results section presents a large amount of data, but the narrative flow between different experiments could be improved. More explicit connections between the various assays and findings would strengthen the overall story.
4. Some of the figure legends lack sufficient detail to fully interpret the data without referring back to the main text. Expanding these would make the figures more standalone.
5. The discussion section is thorough, but could be more focused on interpreting the key findings in relation to the initial aims. It veers into speculation at times without always clearly distinguishing between established results and hypothetical explanations.
6. The conclusions drawn sometimes seem to overreach what is directly supported by the data presented. More measured language in places may be appropriate.
7. There are some minor grammatical and spelling errors throughout that should be corrected.
8. The use of acronyms is inconsistent - some are defined on first use while others are not. This should be standardized.
9. Some of the statistical analyses are not fully described (e.g. specific post-hoc tests used). More detail here would aid reproducibility.
10. The manuscript is quite long and dense. Considering splitting into two separate papers, or moving some data to supplementary materials, may improve readability and impact.

 

Author Response

Reviewer 2

Here are my comments and suggestions:

1. The introduction could be more concise and focused. There is a lot of background information provided, but it could be streamlined to more clearly set up the specific aims and hypotheses of this study.

 

We thank the reviewer for this useful feedback. We have significantly revised the Introduction by rewriting four paragraphs that we think more clearly emphasize specific aims and hypotheses of our study.

Additionally, we have followed the other Reviewer’s suggestion we removed the final paragraph which in the original version contained description of the results and we added a diagram that summarizes DISC1 related effects.

 

2. The methods section is quite detailed, but could benefit from some reorganization. Grouping related methods together (e.g. all behavioral assays, all biochemical assays) may improve readability.

 

As suggested, we have reorganized the methods section to group related methods together, such as behavioral assays and biochemical assays. We agree that this restructuring aims to improve readability and make it easier for readers to follow the experimental procedures.

Additionally, because we moved results (figures) depicting the quantification of the sleep and the length of circadian period into the Appendix, the accompanying methods are now also in the Appendix. This helps to streamline the main Method section without compromising its comprehensiveness.

 

3. The results section presents a large amount of data, but the narrative flow between different experiments could be improved. More explicit connections between the various assays and findings would strengthen the overall story.

 

We agree with the Reviewer, and we have addressed the suggestion by enhancing the narrative flow between the different experiments in the results section. We have made explicit connections between the findings at the start of each subsection to strengthen the overall coherence of the story. With the goal of improving the coherence we also moved Figure panels depicting the quantification of the sleep and the length of circadian period in the Appendix and we describe those results in a significantly shorter form.

 

4. Some of the figure legends lack sufficient detail to fully interpret the data without referring back to the main text. Expanding these would make the figures more standalone.

 

We have revised the figure legends to provide more detailed explanations, ensuring that each figure contains sufficient information for interpreting the results, without mentioning the unnecessary details.

 

5. The discussion section is thorough, but could be more focused on interpreting the key findings in relation to the initial aims. It veers into speculation at times without always clearly distinguishing between established results and hypothetical explanations.

 

We agree that the Discussion needed improvement. We have made significant changes by rewriting four paragraphs where we briefly mention the main findings and interpret them in the context of the published findings. We made sure to not overinterpret our findings. The current version of the Discussion is now significantly shorter and more focused.

 

6. The conclusions drawn sometimes seem to overreach what is directly supported by the data presented. More measured language in places may be appropriate.

 

We have made significant revisions of the Discussion and paid attention to not overinterpret our findings. We have also rewritten the Conclusion subsection and we used much clearer, logical and measured language.

7. There are some minor grammatical and spelling errors throughout that should be corrected.

 

We thank the reviewer for pointing out the grammatical and spelling errors. Additional proofreading has been done, including by two native English speakers.

 

8. The use of acronyms is inconsistent - some are defined on first use while others are not. This should be standardized.

 

We thank the reviewer for highlighting the inconsistency in the use of acronyms. We have standardized the definitions of all acronyms by ensuring each is defined upon first use and for the ease of reading and understanding we repeat the explanations of some acronyms in different subsections. We also excluded acronyms that were used sparingly.

 

9. Some of the statistical analyses are not fully described (e.g. specific post-hoc tests used). More detail here would aid reproducibility.

 

We appreciate suggestion and we have provided additional details on the specific post-hoc tests used and have elaborated on the statistical methods employed throughout the manuscript.

 

10. The manuscript is quite long and dense. Considering splitting into two separate papers, or moving some data to supplementary materials, may improve readability and impact.

 

We have relocated results (figures) depicting the quantification of the sleep and the length of circadian period to the Appendix to enhance the readability and focus of the manuscript. This puts the focus on the activity that directly correlates with the analysis of social interactions and negative geotaxis. Furthermore, the rewritten version of the Discussion emphasizes the connections between the changes in social interactions, locomotor deficits and redox changes and if appropriate connects it with the amount of DISC1 expression in the two lines.  We believe this adjustment improves the cohesion of our work.

We have carefully considered and discussed the Reviewer’s suggestion to split it into two manuscript, however considering that our manuscript only describes new transgenic lines but does not provide mechanistic explanations for observed phenotypes, we feel that the data fits more naturally in a single manuscript.

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors responded to my comments very well. Thank you.