Review for 10.1186/1471-230X-3-17 (2003)

Reviewer's report 
 Differential gene expression profile in the small intestines of mice lacking pacemaker Title: 
interstitial cells of Cajal
Authors: 
Yataro Daigo ( yd206@cam.ac.uk )
Dr Ichiro Takayama ( ichirot@is.icc.u-tokai.ac.jp )
Prof Bruce AJ Ponder ( bajp@mole.bio.cam.ac.uk )
Dr Carlos Caldas ( cc234@cam.ac.uk )
Sean M Ward ( sean@physio.unr.edu )
Kenton M Sanders ( kent@physio.unr.edu )
Masayuki A Fujino ( mfujino@res.yamanashi-med.ac.jp )
 1  25 Apr 2003 Version: Date: 
 Thilo Wedel Reviewer: 
 A paper whose findings are important to those with closely related research Level of interest: 
interests 
 Accept after discretionary revisions Advice on publication: 
The present study is based on previous investigations (Takayama et al.: Differential gene expression 
in the small intestines of wild type and w/wV mice. Neurogastroenterol Motil 2001,13:163-168) 
carried out by the same research group who studied the gene expression profile of the small 
intestine of wild type and w/wV mice, an animal model characterized by a relative loss of ICC 
(intestinal pacemaker cells). 
Using a differential gene display method, seven additional genes have been found to be upregulated 
(n=2) or downregulated (n=5) in w/wV mutants. Among the candidate genes five novel transcripts 
have been identified. Differential gene expression was not influenced by the dietetic state of the 
animals (fasted versus fed). Together with their previous study, the authors yielded a total of 15 genes differentially expressed in the small intestine of w/wV mutant mice. 
Although none of the genes identified have been associated previously with disorders of 
gastrointestinal motility, it is emphasized that the use of modern moleculargenetic technologies may 
allow the recognition of molecular mechanisms responsible for - or at least involved in - the loss of ICC and, thus, the impairment of the gastrointestinal transit. 
COMMENTS 
Abstract 
Background: Skip "that are" 
Conclusions: Replace "comparisons" by "comparison". Complete "interstitial cells" by adding "of 
Cajal". 
Introduction 
Background: 
Paragraph 2, line 8: Add "Absolute or relative loss of ICC..." 
Paragraph 2, line 9: Change "The relationship between motility diseases..." into "The association between diseases of gastrointestinal motility..." Paragraph 2, line 14: Insert reference 15 into the sentence and briefly comment on the results of this 
study. 
Methods 
Paragraph 1, line 6: "Jejunal tissue" is a rather unspecific description of the material obtained. 
Indicate exactly which part of the intestinal wall has been used for the study (tunica muscularis). 
Discussion 
Paragraph 1: First sentence should be divided into two separate statements: (1) identification of 
differentially expressed genes and (2) description of the animal model used Paragraph 1, line 5: Change "small intestines" by into "small intestine". Page 10, paragraph 1, line 1: Change "...underlying motility disorders..." into "underlying GI motility 
disorders..." 
Page 10, paragraph 1, line 3+4: Change "...common to the several motility disorders in which ICC are lost." into "...common to those GI motility disorders characterized by a deficiency of ICC." 
Conclusion 
This sections appears to be somewhat redundant, as it repeats previous statements. It is recommended to either shorten the conclusion or to place it as a final short paragraph into the discussion. 
Figure legend 
Line 3: "G3PDH levels were measured as a control." Does this housekeeping gene correspond to GAPDH? 
General remarks 
The present paper focused on differential gen expression patterns in the small intestine of wild type and w/wV mice - an approach which has been carried out by the same author group in a similar 
manner two years ago (Takayama et al.: Differential gene expression in the small intestines of wild 
type and w/wV mice. Neurogastroenterol Motil 2001,13:163-168). In the present study they yielded seven additional candidate genes. The authors should clarify to which causes the different, that is to say additional, results may be 
attributed. Do they expect even more differentially expressed genes in further studies? It is 
recommended to comprehensively publish the data after the screening of the entire GIT in w/wV mice is completely finished 
Competing interests: 
None declared.