Fig. 1

Gut-associated leukocytes have telomerase-dependent “hyper-long” telomeres, independently of proliferation: A Zebrafish gut paraffin sections A1 showing telomere TelC-Cy3 CCCTAA PNA probe in situ hybridisation (Telo-FISH) in red, combined with anti L-plastin immunofluorescence, in green. Nuclei counterstaining with DAPI in blue. Representative images shown from young (c.5 months) WT and tert^−/−. Yellow arrows are pointing to an example of an L-plastin⁺ cell (green cell) A1.1 Quantifications of the average % of L-plastin ⁺ cells per gut villi, average per animal. B Representative images of Young WT gut with Telo-FISH combined with a near centromeric probe (ZEFRFAL1), which we call Cent-FISH. B1 Relative telomere length (Telo-FISH/Cent-FISH signals) quantifications defining the hyper-long telomere population as above 1.20 when normalised to the relative telomere length of nearby villi epithelial cells. C Representative images of Young WT gut showing a double immunofluorescence staining against PCNA (white) and L-plastin (red) and C1 quantifications of the % (from within the L-plastin⁺ cell population) of PCNA⁺L-plastin⁺. Yellow arrows here point to an example of a double positive (PCNA⁺L-plastin⁺) cell. D Zebrafish Head kidney paraffin sections, showing telomere TelC-Cy3 CCCTAA PNA probe in situ hybridisation (Telo-FISH) in red, combined with anti L-plastin immunofluorescence, in green. Nuclei counterstaining with DAPI in blue. Representative images shown from young (c.5 months) D1 WT and D2 tert^−/−. Yellow arrows are pointing to an example of an L-plastin⁺ cell (green cell) E Quantifications of the % of L-plastin.⁺ with hyper-long telomeres comparing young WT gut with corresponding head kidney. F Relative telomere length quantification in L-plastin and epithelial cells in gut and Head kidney. All scale bars: 50 µm unless stated otherwise in the figure