Domain swapping between FEN-1 and XPG defines regions in XPG that mediate nucleotide excision repair activity and substrate specificity

FEN-1 and XPG are members of the FEN-1 family of structure-specific nucleases, which share a conserved active site. FEN-1 plays a central role in DNA replication, whereas XPG is involved in nucleotide excision repair (NER). Both FEN-1 and XPG are active on flap structures, but only XPG cleaves bubble substrates. The spacer region of XPG is dispensable for nuclease activity on flap substrates but is required for NER activity and for efficient processing of bubble substrates. Here, we inserted the spacer region of XPG between the nuclease domains of FEN-1 to test whether this domain would be sufficient to confer XPG-like substrate specificity and NER activity on a related nuclease. The resulting FEN-1-XPG hybrid protein is active on flap and, albeit at low levels, on bubble substrates. Like FEN-1, the activity of FEN-1-XPG was stimulated by a double-flap substrate containing a 1-nt 3′ flap, whereas XPG does not show this substrate preference. Although no NER activity was detected in vitro, the FEN-1-XPG hybrid displays substantial NER activity in vivo. Hence, insertion of the XPG spacer region into FEN-1 results in a hybrid protein with biochemical properties reminiscent of both nucleases, including partial NER activity

The AE804 and AE806 antibodies label mouse insulin-secreting beta cells by immunofluorescence in histological frozen sections

The AE804 and AE806 antibodies detect the insulin-secreting beta cells by immunofluorescence in mice pancreatic islets

The AK247 and AK248 antibodies label mouse glucagon-secreting alpha cells by immunofluorescence in histological frozen sections

The AK247 and AK248 antibodies detect the glucagon-secreting alpha cells by immunofluorescence in mice pancreatic islets

The RB611 recombinant antibody recognizes human and murine pancreatic polypeptide by immunofluorescence

A new recombinant antibody, RB611, detects human and murine pancreatic polypeptide (PPY) by immunofluorescence on histological sections

RB608, RB609, RB610, RB611 and RB612 antibodies recognize murine pancreatic polypeptide by ELISA

Newly generated recombinant antibodies RB608, RB609, RB610, RB611 and RB612 detect by ELISA the peptidic hormone termed pancreatic polypeptide (PPY)

Stress-induced adaptive islet cell identity changes

The different forms of diabetes mellitus differ in their pathogenesis but, ultimately, they are all characterized by progressive islet β-cell loss. Restoring the β-cell mass is therefore a major goal for future therapeutic approaches. The number of β-cells found at birth is determined by proliferation and differentiation of pancreatic progenitor cells, and it has been considered to remain mostly unchanged throughout adult life. Recent studies in mice have revealed an unexpected plasticity in islet endocrine cells in response to stress; under certain conditions, islet non-β-cells have the potential to reprogram into insulin producers, thus contributing to restore the β-cell mass. Here, we discuss the latest findings on pancreas and islet cell plasticity upon physiological, pathological and experimental conditions of stress. Understanding the mechanisms involved in cell reprogramming in these models will allow the development of new strategies for the treatment of diabetes, by exploiting the intrinsic regeneration capacity of the pancreas