An In Vitro Model of Avian Skin Reveals Evolutionarily Conserved Transcriptional Regulation of Epidermal Barrier Formation

Abstract

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Identification of Chicken Transglutaminase 1 and In Situ Localization of Transglutaminase Activity in Avian Skin and Esophagus

“…Fresh tissue samples were dissected and washed in phosphate-buffered saline (PBS). Chicken in vitro skin models were obtained from a previous study [40]. The samples were placed in cryomolds (Tissue-Tek ® Cryomold ® , Sakura FineTec, Torrance, CA, USA) filled with optimal cutting temperature (OCT) compound (Scigen, Paramount, Canada) and snapfrozen in liquid nitrogen.…”

“…Publicly available TGM1 protein sequences of human (GenBank accession number: NP_000350.1), zebra finch (XP_041568788) and Swainson's thrush (XP_032940238) were used as queries for tBLASTn searches [46] in sequence reads of a chicken in vitro skin model [40] (NCBI accession number: SRX9610284). The reads were translated with the Expasy Translate tool at https://web.expasy.org/translate/ (accessed on 28 September 2021).…”

“…tBLASTn searches using the amino acid sequence of zebra finch TGM1 protein (XP_041568788) as the query revealed the presence of two sequence stretches similar to the last two exons of TGM1 in the chicken genome region between NEDD8 and the genome sequence gap mentioned above (Figure 1A). Next, we performed tBLASTn searches in the RNA-sequence reads that we had previously obtained in a transcriptome analysis of chicken epidermis reconstituted in vitro [40]. Using this approach, we obtained a series of overlapping short reads which, together with the sequence of the TGM1-like exons, besides NEDD8, covered the entire coding sequence of chicken TGM1 (Figure 1A and Figure S1, Table S2).…”

“…TGM1 mRNA was detected in the skin from the back, scutate scales on the legs, reticulate scales from the toes and in the esophagus, but not or only at very low levels in the stomach, lung, heart and kidney of chickens (Figure 2). TGM1 is also expressed in isolated keratinocytes and in the epidermal compartment of chicken skin reconstituted in vitro [40] (Figure 2). By contrast, TGM2 was detected only in lung, heart and kidney (Figure 2).…”

Single-cell transcriptomics defines keratinocyte differentiation in avian scutate scales

“…To the best of our knowledge, a comprehensive gene expression catalog resolving the alternating pattern of soft and hard cornification has not been reported yet. In a recent study, we isolated keratinocytes from chicken leg skin, cultured them in an in vitro model of avian skin and determined their transcriptome 28 . Differentiation of keratinocytes in this culture system induced the expression of many genes, including members of the keratin family 29 , that were not expressed in monolayer cultures.…”