Different protein tyrosine phosphatase superfamilies resulting from different gene reading frames

Protein tyrosine phosphatases (PTPs) are comprised of two superfamilies, the phosphatase I superfamily containing a single low-molecular-weight PTP (lmwPTP) family and the phosphatase II superfamily including both the higher-molecular-weight PTP (hmwPTP) and the dual-specificity phosphatase (DSP) families. The phosphatase I and H superfamilies are often considered to be the result of convergent evolution. The PTP sequence and structure analyses indicate that lmwPTPs, hmwPTPs, and DSPs share similar structures, functions, and a common signature motif, although they have low sequence identities and a different order of active sites in sequence or a circular permutation. The results of this work suggest that lmwPTPs and hmwPTPs/DSPs are remotely related in evolution. The earliest ancestral gene of PTPs could be from a short fragment containing about 90similar to120 nucleotides or 30similar to40 residues; however, a probable full PTP ancestral gene contained one transcript unit with two lmwPTP genes. All three PTP families may have resulted from a common ancestral gene by a series of duplications, fusions, and circular permutations. The circular permutation in PTPs is caused by a reading frame difference, which is similar to that in DNA methyltransferases. Nevertheless, the evolutionary mechanism of circular permutation in PTP genes seems to be more complicated than that in DNA methyltransferase genes. Both mechanisms in PTPs and DNA methyltransferases can be used to explain how some protein families and superfamilies came to be formed by circular permutations during molecular evolution.

重读和动词隐含因果性对代词加工的影响

Numerous studies have shown that accentuation and implicit verb causality influenced pronoun resolution. However, many researchers cannot agree on the time course, as well as they know little about the interaction between the two types of information during comprehending Chinese sentences. The study aimed to explore the effects of accentuation and implicit verb causality on the pronoun processing during spoken Chinese sentences comprehension as well as their time courses, using auditory moving window technique and cross-modal probe paradigm. The main results were: 1) The reading time of the second clause in stressed pronoun condition was significantly longer than that in unstressed pronoun condition. Accentuation influenced the activation level of candidate antecedents. 2) Implicit verb causality influenced the pronoun interpretation during spoken Chinese sentences comprehension. It also affected the activation level of candidate antecedents immediately after people heard the pronoun. 3) There was “the first-mentioned effect” in spoken Chinese sentences comprehension. The effect seemed as if a general phenomenon during the pronoun processing. 4) Accentuation, Implicit verb causality and the first-mentioned effect interacted during the pronoun processing and spoken Chinese sentences comprehension. This study supported the focus hypothesis, indicating accentuation could shift the center of attention even in nonparallel-structure sentences; implicit verb causality influences the pronoun processing immediately; there was interaction between accentuation and implicit verb causality during spoken sentence comprehension.

影响汉语阅读能力发展的相关认知因素及其作用的发展变化

The present cross-sectional study paid attention to Chinese reading acquisition of 391 children from preschool to grade 3 in two elementary schools, and investigated the relationship between orthographic processing skills, morphological awareness, phonological awareness, naming, phonological memory, visual processing skill and reading skills, after controlling the variance of age, nonverbal intelligence and pinyin knowledge. The main results are as follows: Firstly, there are many different language skills as the predictors of Chinese reading success. Orthographic processing skills, morphological awareness, phonological awareness and naming are important in single-character recognition and comprehension. Beside them, the effect of visual processing skill and phonological memory for comprehension are also significant. Among them, the role of orthographic processing skills is the most important, whatever in single-character recognition or in comprehension. Secondly, orthographic processing skills are the most important factors in reading acquisition at low grade and its effect drops obviously after grade 2. Thirdly, morphological awareness is also the factor that cannot be ignored whatever for single-character recognition or for comprehension. Its influence appears in preschool and becomes the only significant predictor of character recognition in grade 3. Furthermore, morphological awareness is more relevant with the development of comprehension. Fourthly, phonological awareness plays the secondary role in Chinese reading acquisition except in grade 2 when its contribution is most of all. And compare with morphological awareness, the effect of phonological awareness is relative low. Fifthly, naming is important through preschool to grade 2. The contribution of phonological memory increases from preschool to grade 3 in comprehension.

工作记忆广度对语篇理解中重读效应的影响

The present study explored the influence of working memory span on accentuation effects in discourse comprehension from the approach of individual difference. High and low working memory span subjects were selected by Reading Span Test. Sentence-by-sentence Auditory Moving Window paradigm was employed to measure the effects of accentuation on discourse comprehension. The on-line processing time of discourse comprehension was compared between consistent accentuation condition, inconsistent accentuation condition and controlled condition. The results indicated that the accentuation effects were influenced by working memory capacity. For low working memory subjects, consistent accentuation speeded up the on-line processing of spoken discourse, inconsistent accentuation slowed down the on-line processing of spoken discourse. But for high working memory span subjects, neither effect was manifested. The only significant difference was found between the condition of inconsistent accentuation and consistent accentuation. During spoken discourse comprehension, there was no significant difference in the on-line processing time between high and low working memory span subjects in consistent accentuation condition as well as in neutral accentuation condition. However, in the condition of inconsistence accentuation, low span subjects spent significantly more time on the on-line processing of spoken discourse than high span subjects. The results could be explained by the controlled attention view of working memory.