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Biochemical Genetics (v.40, #1-2)

Cloning and Expression Pattern of a Spermatogenesis-Related Gene, BEX1, Mapped to Chromosome Xq22 by Quan-Sheng Yang; Fang Xia; Shao-Hua Gu; Hong-Ling Yuan; Jing-Zhong Chen; Qi-Sheng Yang; Kang Ying; Yi Xie; Yu-Min Mao (pp. 1-12).

Through screening a human fetal brain cDNA library, a cDNA similar to the mouse Bex1 was isolated. This new gene was named brain expressed X-linked protein 1 (BEX1). Northern blot analysis revealed a 1.0 kb transcript highly expressed in brain, pancreas, testis, and ovary, with lower levels present in heart, placenta, liver, kidney, spleen, thymus, prostate, small intestine, colon ( no mucus), thyroid, spinal cord, and adrenal gland. No hybridization signal was seen in lung, skeletal muscle, peripheral blood leukocyte, stomach, lymph node, trachea, and bone marrow. The BEX1 gene was localized to chromosome band Xq22 between markers between DXS990 and DXS1059 by screening Stanford radiation hybrid G3 panels. In situ hybridization of mouse testis using BEX1 as a probe detected the signal in the pachytene spermatocytes and spermatids but not in spermatogonia. Furthermore, it was not detected at 6, 9, and 12 days postpartum, was present in low amount on Days 15 and 18 and its expression increased sharply after the initiation of puberty (about 21 days) in mouse testis.

Keywords: radiation hybrid; spermatogenesis; pachytene spermatocyte; spermatid; X chromosome; spermatogonia; sex body

Differential Effects of the Kit^W Mutation with Other Kit Allelic Combinations on Male Sterility Among Inter- or Intrasubspecific Hybrids in Mice by Abeer El-Nahas; Samir El-Shazly; Said El-Fiky; Tomomasa Watanabe (pp. 13-25).

The combination of the Kit ^W mutation and Kit ^S allele from Mus spretus leads to male hybrid sterility. The effects of other combinations between Kit ^W and Kit ^M from Mus m. molossinus or Kit ^N from Mus m. musculus on male reproductive ability were examined in this study. The Kit ^W/Kit ^M and Kit ^W/Kit ^N males were fertile and showed the normal pattern of spermatogenesis in most seminiferous tubules. There were two amino acid substitutions in the protein deduced from the cDNA sequence coded by the Kit ^M allele sequence and three in the Kit ^M allele compared with the protein from the + Kit allele of C57BL mice. These amino acid exchanges had no effect on the fertility of Kit ^W/Kit ^M and Kit ^W/Kit ^N males. Therefore, comparing the sequence data from cDNA coded by Kit ^M and Kit ^N alleles with that for the Kit ^S allele, we concluded that one or more amino acid exchanges in the extracellular domain would be the cause of male hybrid sterility in the Kit ^W/Kit ^S combination; these substitutions are Phe to Ser at position 72, Thr to Ala at 95, Ser to Arg at 101, Leu to Pro at 123, and Ile to Met at 1303

Keywords: male hybrid sterility; Kit gene; W allele; wild mice

Apolipoprotein C Polymorphism in Sheep: Allele Frequencies and Association with Plasma Lipid and Lipoprotein Levels by Kenji Tsunoda; Shohei Hamato; Shoei Kurosawa; Ayako Shirato; Yaetsu Kurosawa; Koichiro Fujimaki; Masahiro Muto; Keizo Sato (pp. 27-39).

The genetic polymorphism of apolipoprotein C in normal plasma of four European sheep breeds (Suffolk, Corriedale, Cheviot, and Finn) was first detected using one-dimensional polyacrylamide gel isoelectric focusing (pH 2.5–5.0) followed by immunoblotting with antihuman apolipoprotein CII antibody. Six phenotypes (1-1, 2-1, 2-2, 3-1, 3-2, and 3-3) were identified in the 4.3–4.8 pH range, consisting of the combination of three isoform groups. On the basis of family and population data, these phenotypes were controlled autosomally by three codominant alleles, designated APOC*1, APOC*2, and APOC*3, the first being the most common allele. The frequency distributions of these alleles were similar between the Suffolk and Corriedale sheep, and between the Cheviot and Finn sheep. The former breeds had a significantly lower APOC*2 frequency than the latter breeds (P< 0.001). The mean plasma total-, HDL- and LDL-cholesterol levels of type 3-1 animals were significantly higher compared to type 1-1 animals in the Suffolk sheep (P≦ 0.04). However, these differences were not seen in the Corriedale sheep

Keywords: apolipoprotein C; genetic polymorphism; isoelectric focusing; plasma lipoprotein; domestic sheep

Length Polymorphism of Thymidylate Synthase Regulatory Region in Chinese Populations and Evolution of the Novel Alleles by Huai-Rong Luo; Xue-Mei Lü; Yong-Gang Yao; Nobuyuki Horie; Keiichi Takeishi; Lynn B. Jorde; Ya-Ping Zhang (pp. 41-51).

The tandemly repeated 28-bp sequence in the 5′-terminal regulatory region of human thymidylate synthase (TSER), which has been reported to be polymorphic in different populations, was surveyed in 668 Chinese from 9 Han groups, 8 ethnic populations, and 36 individuals representing a three-generation pedigree. Amplified fragments were separated by electrophoresis on 4% agarose gel. In addition to the reported double and triple repeats of the 28-bp sequence in TSER, we also detected a novel quintuple repeat in this region. The transient expression activity of TSER with the quintuple repeat is almost the same as that of the reported TSER with the triple repeat. All three alleles of the repeat type (2, 3, and 5) were further confirmed by sequencing. The frequencies of the TSER allele 2 and 3 were 18.82 and 81% in totally unrelated Chinese samples, respectively, while the frequency of allele 3 was variable in different Chinese populations with a range from 62 to 95%. On the basis of the sequences of the different alleles, the existence of the tandem repeats in each allele might be explained by slipped-strand mispairing during DNA replication.

Keywords: TSER; thymidylate synthase; length polymorphism; Chinese population; evolution

Noncryogenic Preservation of Mammalian Tissues for DNA Extraction: An Assessment of Storage Methods by C. William Kilpatrick (pp. 53-62).

Reliable field methods for the storage of tissues to be used for DNA extraction and amplification are critical to many studies employing molecular techniques. Protection from DNA degradation was compared among three commonly used methods of noncryogenic storage of tissues over a time scale of 2 years. All three methods prevented DNA degradation during storage for at least 6 months. DMSO (dimethyl sulfoxide)-salt solution provided the best protection from DNA degradation of tissues stored for up to 2 years. High molecular weight DNA was recovered from lysis buffer in which tissue was stored for 2 years, however, moderate amounts of degraded DNA was also present. High molecular weight DNA was recovered from tissues stored in ethanol for 2 years, however, the yield was relatively small compared to the other two noncryogenic storage techniques. Much of the DNA degradation in ethanol preserved tissues appeared to occur during the extraction procedure and can be reduced by soaking the tissue in lysis buffer for a few hours prior to beginning the extraction. The yield of PCR products was greatest from DNA extracted from DMSO-salt solution preserved tissues, whereas DNA from tissues stored in either lysis buffer or ethanol produced lower yields.

Keywords: tissue storage; noncryogenic; DNA extraction; degradation

Note: Diversity Analysis of Indian Tetraploid Wheat Using Intersimple Sequence Repeat Markers Reveals Their Superiority over Random Amplified Polymorphic DNA Markers by S. Pujar; S. A. Tamhankar; V. S. Gupta; V. S. Rao; P. K. Ranjekar (pp. 63-69).

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Biochemical Genetics (v.40, #1-2)

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Biochemical Genetics (v.40, #1-2)