Transcriptome analysis of the uterus of hens laying eggs differing in cuticle deposition

Abstract

Background: Avian eggs have a proteinaceous cuticle. The quantity of cuticle varies and the deposition of a good cuticle in the uterus (Shell-gland) prevents transmission of bacteria to the egg contents. Results: To understand cuticle deposition, uterus transcriptomes were compared between hens with i) naturally good and poor cuticle and, ii) where manipulation of the hypothalamo-pituitary-gonadal-oviduct axis produced eggs with or without cuticle. The highest expressed genes encoded eggshell matrix and cuticle proteins, e.g. MEPE (OC-116), BPIFB3 (OVX-36), RARRES1 (OVX-32), WAP (OVX-25), and genes for mitochondrial oxidative phosphorylation, active transport and energy metabolism. Expression of a number of these genes differed between hens laying eggs with or without cuticle. There was also a high expression of clock genes. PER2, CRY2, CRY1, CLOCK and BMAL1 were differentially expressed when cuticle deposition was prevented, and they also changed throughout the egg formation cycle. This suggests an endogenous clock in the uterus may be a component of cuticle deposition control. Cuticle proteins are glycosylated and glycosaminoglycan binding genes had a lower expression when cuticle proteins were deposited on the egg. The immediate early genes, JUN and FOS, were expressed less when the cuticle had not been deposited and changed over the egg formation cycle, suggesting they are important in oviposition and cuticle deposition. The uterus transcriptome of hens with good and poor cuticle deposition did not differ. Conclusions: We have gained insights into the factors that can affect the production of the cuticle especially clock genes and immediate early genes. We have demonstrated that these genes change their expression over the period of eggshell formation supporting their importance. The lack of differences in expression between the uterus of hens laying eggs with the best and worse cuticle suggest the genetic basis of the trait may lie outside the oviduct.

Effect of organic and inorganic dietary selenium supplementation on gene expression in oviduct tissues and Selenoproteins gene expression in Lohman Brown-classic laying hens

“…The current study found that regardless of dietary Se treatments, mRNA expression of OCX-32 and OCX-36 was up-regulated in the shell gland than in magnum tissue. Poyatos et al [ 57 ] and Yin et al [ 44 ] identified highly expressed OCX-32 precursors in the shell gland with egg, which is consistent with our findings. Similarly, Yin et al [ 60 ] found that the OCX-32 gene was expressed higher in the distal oviduct (isthmus and shell gland) than in the proximal oviduct (magnum and shell gland), suggesting that it is secreted by the glandular epithelium of the shell gland [ 61 ].…”

“…Regardless of the treatment groups, the results showed higher mRNA expression of OC-17 and OC-116 in the shell tissue than in magnum. This was confirmed by published data [ 19 , 44 , 46 , 57 ], who found higher OC-116 genes mRNA expression in the shell gland tissue. Furthermore, there has been an interaction between organic matrix and inorganic minerals in chicken uterine fluid, resulting in tough and calcification of eggshell [ 19 ].…”

Circadian miR-218-5p targets gene CA2 to regulate uterine carbonic anhydrase activity during egg shell calcification

“…Eggshell calcification in the uterus of laying hens involves multiple cellular and molecular processes, including calcium carbonate secretion, transport and biological mineralization ( Sah et al, 2018 ; Khan et al, 2019 ). It has been reported that circadian clock is a major component and significantly controls cuticle deposition in the uterus of laying hens ( Poyatos et al, 2020 ). We found functional clocks in the chicken infundibulum and uterus ( Zhang et al, 2016 ; Zhang et al, 2017 ).…”

A transcriptome analysis for 24-hour continuous sampled uterus reveals circadian regulation of the key pathways involved in eggshell formation of chicken

“…Recent finding reported that endogenous clock is a major component and significantly controls cuticle deposition in the uterus of laying hens ( Poyatos et al, 2020 ). To clearly understand the control mechanisms of uterine clock exerted on CCGs regarding the phases in a day, a systemic understanding of the dynamic transcriptional regulations of the circadian clock is necessary.…”