Table 2.

List of genes with functional annotations proposed as markers of avian oviduct epithelial cells

Gene symbol/	Gene name	Species/ NCBI reference	Gene function (Gene atlas)	Biological process	Reference (Function)	% of identity with human protein sequence	% of identity with quail genomic sequencea
ESR1	estrogen receptor 1	G. gallus 396,099	Encodes the protein estrogen receptor alpha, plays role in the sex differentiation of reproductive tract, regulates the expression of oviduct genes	4A- nuclear receptor; transcription regulator; binding estradiol, epithelial cell development, cell differentiation	[34, 39]	79	99
		C. japonica 107,311,566		Transcription regulator; binding estradiol, epithelial cell development, cell differentiation	[40]	n/a
OVAL	Ovalbumin-SERPINB14	G. gallus 396,058	Encodes ovalbumin in Ov-serpin family, located in extracellular space	Oviduct secretome, binds calcium, responds to steroid hormones, constitutes egg white	[41]	41	93
		C. japonica 107,309,565		Oviduct secretome, constitutes egg white, responds to steroid hormones	[42]	n/a
OVM	SPINK7- serine peptidase inhibitor, Kazal type 7	G. gallus 416,236	Encodes ovomucoid protein to the extracellular space, responds to steroid hormones, binds IgE, IgG	Secreted as egg white protein, allergenic as a food component, responsive to steroid hormones (progesterone), allergenic component of an egg white	[43, 44]	44	96
		C. japonica 107,320,484				n/a
KRT5	keratin 5	407,779	Encodes protein keratin 5, type II cytoskeletal 5	Interacts with KRT14 to form cytoskeleton of basal epithelium, expressed in stem cells of fallopian tube, epithelial differentiation	[15]	80b	98
KRT14	keratin, type I cytoskeletal 14	408,039	Marker of the stratified epithelium as keratin filament	Interacts with KRT5 to form the cytoskeleton of basal epithelium, expressed in tumor cells of fallopian tube, marker of chicken keratinocytes, epithelial differentiation	[26]	69	100
OCLN	occludin	G. gallus 396,026	Encodes protein occludin, marker of tight junctions in epithelial cells	Component of plasma membrane, role in cellular binding, forms tight junctions	[26]	47	96
		C. japonica 107,325,447				n/a
CD44	cell surface glycoprotein CD44	G. gallus 395,666	Encodes CD44 antigen, marker of epithelial stem cells in fallopian tube	Role in cell adhesion (cell to cell) and postponement of the apoptotic process	[15]	48	100
		C. japonica 107,314,385				n/a
LGR5	Leucine-rich repeat containing G protein-coupled receptor 5	G. gallus 427,867	Encodes protein LGR5, induced by Wnt/β-Catenin signaling	Marker of stem cells in the ovary and tubal epithelia	[14]	30c	99
		C. japonica 107,310,333				n/a
MSI-1	Musashi-1; Musashi RNA binding protein- 1	G. gallus 416,979	Marker of epithelial early lineage, marker of stem cells in human endometrium	Maintains proliferation and multipotent potential of epithelial cells (emerging from Müllerian duct)	[45]	80	100
		C. japonica 107,321,418			[31]	n/a
NANOG	Nanog homebox	G. gallus 100,272,166	Encodes transcriptional factor of pluripotency: homebox protein NANOG, Marker of stem cells in ovarian epithelium	Maintains stem cell population, chicken stem cell marker	[32]	89	100
		C. japonica 107,318,297			[46]	n/a
OCT4/ cPOUV	POU domain class 5 transcription factor 3, Octamer-binding protein 4	427,781	Encodes transcription factor POU5F3	Maintains cell pluripotency, maintains population of somatic stem cells, shows responses to wounding	[33]	43	97
SOX9	SRY sex determining region Y-box 9	G. gallus 374,148	Encodes HMG box transcription factor, marker of epithelial early lineage, transcription epithelial-mesenchymal transition marker	Negatively regulates the differentiation of epithelial cells, maintains the population of somatic stem cells, plays role in transdifferentiation; regulation of cell adhesion, activated during chondrogenesis in chicken	[28]	99	100
		C. japonica 107,322,214			[29]	n/a

^aBlasted with http://viewer.shigen.info/uzura/blast_result.php. ^bsimilarity for gene is given; no protein sequence of protein KRT5 is available for G. gallus. ^cUNIPROT blasting tool shows for only 30% identity of a G. gallus sequence with human LGR5, but the same protein sequence shows 95% identity with human VAV3 GDP/GTP exchange factor. For a quail, only 900 proteins are annotated in existing UniProt databases. Thus, when a gap in quail database [22] limits the interpretation of a sequence, a relevant genomic alignment onto chicken was performed [23]. Depending on the database used (ENSEMBL, NCBI, and/or UniProt), sequences of the genes selected for this study had 89%–100% similarity. Thereby, gene expression assays developed were comparable between both species