TY - JOUR ID - 2381 TI - Isolation of a cDNA coding for an ubiquitin-conjugating enzyme UBC1 of tomato - the first stress-induced UBC of higher plants JO - FEBS Lett. PY - 1997 SP - 211-215 AU - Feussner, K. AU - Feussner, I. AU - Leopold, I. AU - Wasternack, C. AU - VL - 409 UR - DO - 10.1016/S0014-5793(97)00509-7 AB - A clone of an ubiquitin‐conjugating enzyme (UBC) was isolated from a λ‐ZAP‐cDNA library, generated from mRNA of tomato (Lycopersicon esculentum) cells grown in suspension for 3 days. The open reading frame called Le UBC1, encodes for a polypeptide with a predicted molecular mass of 21.37 kDa, which was confirmed by bacterial overexpression and SDS‐PAGE. Database searches with Le UBC1 showed highest sequence similarities to UBC1 of bovine and yeast. By Southern blot analysis Le UBC1 was identified as a member of a small E2 subfamily of tomato, presumably consisting of at least two members. As revealed by Northern blot analysis Le UBC1 is constitutively expressed in an exponentially growing tomato cell culture. In response to heat shock an increase in Le UBC1‐mRNA was detectable. A strong accumulation of the Le UBC1‐transcript was observed by exposure to heavy metal stress which was performed by treatment with cadmium chloride (CdCl2). The cellular uptake of cadmium was controlled via ICP‐MS measurements. The data suggest that like in yeast, in plants a certain subfamily of UBC is specifically involved in the proteolytic degradation of abnormal proteins as result of stress. A2 - C1 - Molecular Signal Processing ER -