PONE-D-20-14270

Expression characteristics and regulatory mechanism of Apela gene in liver of chicken (Gallus gallus)

PLOS ONE

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Additional Editor Comments (if provided):

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: N/A

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

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Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: In this manuscript Tan et al shew that the expression pattern of apela at different tissues at two time points and found that apela was expressed highly in liver et al. Finally Tan et al wanted to prove the 17β-estradiol induce the expression of apela to involves in liver lipid metabolism. This work is inteseting but far more work is needed to confirm the conclusion (experiments and discussion).

1, why liver et al while not ovary or another related tissues displayed high expression of apela? discussion was needed here.

2, the authors used different ER inhibitor to evaluate which receptor was in the cascade to control apela expression, it looks reasonable. While we suggest the author to check the expression of the different receptors in different tissues at the two time points, that is benefit to get the conclusion.

3, the authors wanted to show apela mediates ER to regulate liver lipid metablism, and used the word "likely", but I suggest to do more work to confirm it since it is easy to do. If not we suggest not to discuss this point in the manuscript. You know there is a big gap here.

4, the disscussion only list the experiment again while not discuss the question about this study. In addition, we suggested the authors discuss the study within a deep way.

Reviewer #2: The authors reported the cloning of Apela/Elabela gene in chicken, its expression across the tissues and inducible expression in the liver of hens or hepatocytes at the peak-laying stage or by 17beta-estradiol treatment. They concluded that Apela may be involved in liver lipid metabolism of laying chicken through estrogen-induced regulation. The cloning of Apela in chicken was reported 2 years ago, in which Apelin and Apelin receptor were also well characterized (PMID: 30631305). What’s new here is that inducible expression of Apela in the liver and its correlation with ApoVLDLII expression.

Comments

1. Apelin (Apln) and Apelin receptor (Aplnr) should be examined in the liver of hens and hepatocytes at the peak-laying stage and by 17beta-estradiol treatment, respectively.

2. A key question is whether Apela gene in chicken express the peptide. Since the 3’UTR of Apela mRNA has regulatory roles on gene expression depending on species (PMID: 25936916), it would be possible that chick Apela may only serve as a non-coding RNA.

3. It should be clarified whether Apela peptide indeed regulate lipid metabolism in the liver of laying chicken. It is also possible that Apela may regulate lipid metabolism in other organs in endocrine manner. These points should be investigated experimentally.

4. Compared with induction of ApoVLDLII, increase of Apela expression is modest at the peak-laying stage. Down-regulation of Apela expression in pancreas is more robust. This is also needed to examine more carefully together with expression of Apln and Aplnr.

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Reviewer #1: No

Reviewer #2: No

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Expression characteristics and regulatory mechanism of Apela gene in liver of chicken (Gallus gallus)

PONE-D-20-14270R1

Dear Dr. Liu,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. One reviewer did not like your answer to the question on the possible non-coding function of the APELA-mRNA you describe. But you mention the publication (ref 19) about noncoding functions of the mRNA in human ESCs and the paper (ref 42) showing that it also produces a peptide in the same cells, which is sufficient to address this issue in my opinion.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Michael Bader

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: No

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: No

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Your group found that the interesting expression pattern of apela/aplnr in chicken, and checked tdhe relationship between them and ER signaling, it is intersting and useful for the futher study. while the function of apela in liver metabolism need far more work to address.

Reviewer #2: Apela is a gene encoding a peptide ligand for Apelin receptor, but the authors did not clarify whether their identified gene is Apela or related pseudogene or non-coding RNA. The authors did not address the comments raised by this reviewer experimentally.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Sizhou Huang

Reviewer #2: No