Sitarz M, Wirth-Dzieciolowska E, Demant P
Department of Genetics and Laboratory Animal Breeding, M.Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
Neoplasma. 2000;47(3):148-50.
Analysis of the loss of heterozygosity at the D5Mit143 locus was done for thymic lymphlomas induced by gamma-irradiation of mice from two reciprocal backcrosses (BALB/c x CcS-13)F1 x BALB/c and (BALB/c x CcS-13)F1 x CcS-13. BALB/c mice are susceptible to gamma-ray induction of lymphomas. The CcS-13 strain is one of 20 CcS/Dcm (CcS) series of recombinant congenic strains, and the CcS-13 mice are resistant to gamma-radiation-induced lymphomas [1, 8]. Our preliminary tests show 50% (6/12) frequency of allelic loss at the D5Mit143 locus in thymic lymphomas induced by gamma-irradiation of the mice from (BALB/c x CcS-13)F1 x BALB/c backcross. Yet, in gamma-radiation-induced lymphomas from the backcross made in opposite direction, namely, (BALB/c x CcS-13)F1 x CcS-13, the analysis with the DSMit143 marker revealed low incidence of the loss of heterozygosity, 6.7% (15). The D5Mit143 locus resides in the distal part of chromosome 5, close to the telomere. Allelic loss of heterozygosity at the D5Mit143 locus showed strain specificity. In each case, the lost allele derived from the CcS-13 resistant strain. Our current results and previously done) linkage analysis [8] let us to suspect existence of a putative tumor suppressor gene for gamma-radiation-induced lymphoma at the region of murine chromosome 5.
对来自两个正反交回交（BALB/c×CcS - 13）F1×BALB/c和（BALB/c×CcS - 13）F1×CcS - 13的经γ射线照射诱导产生胸腺淋巴瘤的小鼠，进行了D5Mit143位点杂合性缺失分析。BALB/c小鼠易受γ射线诱导产生淋巴瘤。CcS - 13品系是20个CcS/Dcm（CcS）系列重组近交系之一，CcS - 13小鼠对γ射线诱导的淋巴瘤具有抗性[1, 8]。我们的初步试验表明，在（BALB/c×CcS - 13）F1×BALB/c回交的经γ射线照射诱导产生胸腺淋巴瘤的小鼠中，D5Mit143位点的等位基因缺失频率为50%（6/12）。然而，在反向回交即（BALB/c×CcS - 13）F1×CcS - 13产生的经γ射线诱导的淋巴瘤中，用D5Mit143标记进行分析发现杂合性缺失发生率较低，为6.7%（1/15）。D5Mit143位点位于5号染色体的远端，靠近端粒。D5Mit143位点杂合性的等位基因缺失表现出品系特异性。在每种情况下，丢失的等位基因均来自CcS - 13抗性品系。我们目前的结果以及之前进行的连锁分析[8]使我们怀疑在小鼠5号染色体区域存在一个假定的γ射线诱导淋巴瘤的肿瘤抑制基因。
