太子参环肽B(Heterophyllin B,HB)的酶环化反应

利用从Pseudostellariaheterophylla提取分离的粗酶PH-1,以链八肽NH2-Gly1-Gly2-Leu-Pro-Pro-Pro-Ile-Phe-COOH(4)为底物成功地进行了太子参环肽B(heterophyllinB(HB))的环化反应,并利用TLC,HPLC,MS,NMR以及同位素标记等手段对反应产物进行了分析和确证.

2'-'5-三腺苷酸对巨噬细胞腺苷酸环化酶和cAMP-磷酸二酯酶活性的影响

1989年,我们曾首次证实干扰素作用介导物pppA2＇p5＇A2＇p5＇A(2＇-5＇-三腺苷酸,2＇-5＇P_3A_3)能引起巨噬细胞中cAMP,cGMP水平升高,表明这两种环核苷酸在传递干扰素信息中起着重要作用。在上述研究的基础上,本研究观察了2＇-5＇P_3A_3对腺苷酸环化酶(AC)和cAMP-磷酸二酯酶(cAMP-PDE)两种酶的活性影响,结果发现,1×10^(-6)mol/L的2＇-5＇P_3A_3可显著增加AC的活性,而对cAMP-PDE活性沒有显著影响,这说明2＇-5＇P_3A_3引起的细胞内cAMP水平的升高是由于激活AC而使其生成增多,而不是抑制cAMP-PDE而使其降解减少的结果。

鸟苷酸环化酶C在大肠癌患者外周血中的表达及其临床意义

目的探讨鸟甘酸环化酶C(GCC)在大肠癌患者外周血中的表达及其临床意义。方法采用RT-PCR法对32例大肠癌患者、25例大肠良性病变患者、30例健康体检者外周血中GCC表达情况进行检测,并对大肠癌病理指标与GCC mRNA表达阳性率之间关系进行研究。结果 32例大肠癌患者中,GCC mRNA的阳性检出率为65.63%(21/32),良性组中GCC mRNA的阳性检出率为20.00%(5/25),而对照组中未见GCC mRNA表达;三组外周血中表达阳性率差异具有统计学意义(P<0.05)。大肠癌患者GCC mRNA表达水平与Duke分期、淋巴结转移和肝转移密切相关(P<0.05),与年龄、性别、肿瘤大小等无关(P>0.05)。结论 GCC mRNA在大肠癌患者外周血中阳性表达率较高,特别是复发或转移病例,可作为大肠癌术后复发、转移的早期检测指标之一。

γ谷氨酰环化转移酶对斑马鱼早期发育的影响

γ谷氨酰环化转移酶(γ-Glutamyl cyclotransferase,GGCT)是谷胱甘肽循环过程中催化L-γ-GlutamylL-amino acid分解为L-amino acid和5-oxoprodline的关键酶,在防止细胞氧化性损伤中发挥重要作用。研究以斑马鱼为模型,利用吗啡啉(Morpholino,MO)敲降GGCT,发现早期胚胎发育出现脑部发育缓慢、尾短弯曲和环心室水肿等异常表型,原位杂交检测发现脑发育相关标记基因shha、wnt8b与fgf8的表达发生改变。体外转录ggct-m RNA与GGCT-MO共注射,畸形率降低,部分脑部标记基因表达回复正常。此外,使用化学阻断剂阻断GGCT上游的γ谷氨酰转肽酶(γ-Glutamyl transpeptidase,GGT)和下游的5羟脯氨酸酶,斑马鱼胚胎产生发育停滞和水肿表型。敲降GGCT和阻断GGT都降低了胚胎的谷胱甘肽(Glutathione,GSH)的含量,研究表明γ谷氨酰环化转移酶可能通过谷胱甘肽循环在斑马鱼早期胚胎发育过程发挥重要作用。

二萜合酶标记底物的设计与合成

从二萜类天然产物Cyclooctatin的环化机理猜想出发,设计[2-2H]GGDP(GGDP:香叶基香叶基焦磷酸)、[9-2H2]GGDP、[14-2H]GGDP等氘代底物,以供研究二萜合酶环化反应机理,并设计[2-F]GGDP氟代底物用于与酶的共结晶研究,以验证猜想的正确性。均以反式-反式金合欢醇为起始原料,分别利用乙酰乙酸甲酯双负离子和单负离子偶联的方法实现碳链的延长,完成了[2-2H]GGDP和[2-F]GGDP的合成工作。在[2-2H]GGDP合成中,β-酮酸酯经D2O交换在C-2位引入氘原子;在[2-F]GGDP合成中,与乙酰乙酸甲酯单负离子偶联后经Krapcho脱羧反应和Horner-WadsworthEmmons反应在C-2位引入F原子。该研究为[9-2H2]GGDP、[14-2H]GGDP的合成积累了经验,也为后续进一步研究酶环化反应机制奠定了基础。

KRAS条件突变小鼠肺腺癌模型的构建

目的:旨在建立基因编辑的小鼠肺腺癌模型,探究肺腺癌在不同时间点的发展情况以及不同性别小鼠成瘤的差异。方法:利用KRAS^(LSL-G12D)条件突变的C57BL/6J小鼠,通过繁衍扩增鉴定后,采用气管插管递送载有环化重组酶的腺病毒(Ad-Cre)到小鼠肺组织,诱导KRAS基因的突变表达,从而引发肺部肿瘤。分别在感染后1~8个月收集小鼠全肺,石蜡包埋切片后进行HE染色,比较不同时间段及不同性别小鼠肺腺癌成瘤情况。结果:随着递送Ad-Cre的时间增加,小鼠肺腺癌成瘤比例增加,在递送Ad-Cre后6个月成瘤率达100%,同时成瘤的数量和大小也随着时间延长而增长。在成瘤的小鼠肺腺癌中,除感染Ad-Cre后1个月的病变表现为不典型增生外,在感染2个月后的成瘤肿块中均形成了浸润性肺腺癌。此外,不同性别的小鼠在肺腺癌成瘤的表现上无明显差异。结论:KRAS^(LSL-G12D)条件突变小鼠通过气管插管递送Ad-Cre能有效构建肺腺癌模型,且不同性别小鼠肺腺癌的成瘤率没有显著差异。

γ-谷氨酰环化转移酶对临床判断淋巴结阴性甲状腺微小乳头状癌中央区淋巴结转移的预测价值

目的:探讨γ-谷氨酰环化转移酶(GGCT)预测临床判断淋巴结阴性(cN0)期甲状腺微小乳头状癌(PTMC)中央区淋巴结转移(CLNM)的临床价值。方法:回顾性分析华中科技大学同济医学院附属同济医院甲状腺乳腺外科2021年8月至2022年3月收治的108例cN0期PTMC患者的临床及病理资料,通过酶联免疫吸附实验(ELISA)检测病灶细针穿刺(FNA)洗脱液GGCT的表达含量,应用受试者工作曲线(ROC)曲线评估GGCT预测CLNM的临床价值,构建单因素和多因素回归模型,分析与CLNM相关的危险因素。结果:伴有CLNM的样本GGCT含量明显高于不伴有CLNM的样本[(2.09±0.53)ng/ml比(1.29±0.24)ng/ml,t=3.34,P<0.05];ROC曲线表明GGCT预测CLNM的敏感度为76.09%,特异度为85.48%,最佳临界值为1.60 ng/ml;单因素分析结果显示,年龄[<55岁69例,无CLNM比伴有CNLM=40∶29,≥55岁39例,无CLNM比伴有CNLM=22∶17,χ^(2)=0.02,P>0.05]、性别[女80例,无CLNM比伴有CNLM=49∶31,男28例,无CLNM比伴有CNLM=13∶15,χ^(2)=1.86,P>0.05]、多灶性情况[多灶32例,无CLNM比伴有CNLM=15∶17,单灶76例,无CLNM比伴有CNLM=47∶29,χ^(2)=2.06,P>0.05]以及是否合并有桥本甲状腺炎[合并33例,无CLNM比伴有CNLM=23∶10,未合并75例,无CLNM比伴有CNLM=39∶36,χ^(2)=2.94,P>0.05],与CLNM无关,而肿瘤直径[>5 mm 54例,无CLNM比伴有CNLM=20∶34,≤5 mm 54例,无CLNM比伴有CNLM=42∶12,χ^(2)=18.33,P<0.05]、是否伴有甲状腺外侵犯[伴有20例,无CLNM比伴有CNLM=6∶14,未伴有88例,无CLNM比伴有CNLM=56∶32,χ^(2)=7.54,P<0.05]以及术前FNA洗脱液GGCT含量[>1.60 ng/ml 44例,无CLNM比伴有CNLM=9∶35,≤1.60 ng/ml 64例,无CLNM比伴有CNLM=53∶11,χ^(2)=41.47,P<0.05]与CLNM相关。多因素Logistic分析结果表明,术前FNA洗脱液GGCT含量高于1.60 ng/ml[比值比(OR)=6.99,95%可信区间(CI):2.77~18.20,P<0.05]和肿瘤直径>5 mm(OR=5.67,95%CI:1.75~18.35,P<0.05)为cN0期PTMC发生CLNM的独立危险因素。结论:术前检测FNA洗脱液中GGCT含量可作为预测cN0期PTMC是否发生CLNM的有效手段。

Xanthophyll Cycle and Its Molecular Mechanism in Photoprotection

When plants absorb more light than that can be used for photosynthesis, the excessive energy can cause photoinhibition and even photooxidation of photosynthetic apparatus. Xanthophyll cycle-dependent photo-protection is believed to be the main mechanism for plants to deal with excessive light energy. This review focuses on molecular biological aspects and regulations of violaxanthin de-epoxidase and zeaxanthin epoxidase involved in xanthophyll cycle. We will summarize the functions of xanthophyll cycle, especially recent advances in its thermal dissipation mechanism of photoprotection. Some interesting issues deserving further study will be discussed.

Cloning and Expression Analysis of Violaxanthin De-Epoxidase (VDE) cDNA in Wheat

Violaxanthin de-epoxidase (VDE) is the key enzyme in the xanthophyll cycle and protects plant photosynthetic apparatus from the damage of excessive light. A wheat (Triticum aestivum L cv. Xiaoyan 54) VDE cDNA was obtained using RT-PCR method. Its deduced protein sequence shares high identity with that of Arabidopsis and rice. Southern blot revealed that there are three copies of VDE gene per haploid genome of wheat. VDE transcript levels were higher in green leaf than in root, seed and etiolated leaf. Northern blotting analysis indicated that VDE mRNA level is induced during greening process of etiolated wheat seedling and increased by intense light illumination.

膀胱尿路上皮癌组织中γ-谷氨酰环化转移酶的表达及其临床意义

目的探讨膀胱尿路上皮癌组织中γ-谷氨酰环化转移酶(GGCT)的表达及其临床意义。方法收集2011年1月至2013年5月来自潍坊市人民医院的86例膀胱尿路上皮癌和10例癌旁正常膀胱黏膜组织,应用免疫组化染色方法检测GGCT蛋白的表达,并分析其与临床病理特征及预后的关系。结果 86例膀胱尿路上皮癌组织中GGCT表达阳性率为61.6%(53/86)。GGCT蛋白主要在肿瘤细胞的细胞质中表达,部分病例的细胞核中也有表达。GGCT蛋白的表达水平与膀胱尿路上皮癌的肿瘤最大径(P=0.025)、病理分级(P<0.001)和病理分期(P=0.020)有关。在非肌层浸润性膀胱尿路上皮癌中,T1期患者膀胱尿路上皮癌组织中GGCT蛋白的表达高于Ta期患者(P=0.034),GGCT阳性患者的无复发生存率低于GGCT阴性患者(P=0.029)。Cox多因素回归分析显示,肿瘤数量(OR=3.320,P=0.024)和病理分期(OR=5.029,P=0.009)是非肌层浸润性膀胱尿路上皮癌患者无复发生存的独立影响因素。结论 GGCT在膀胱尿路上皮癌组织中高表达,与膀胱尿路上皮癌的恶性生物学行为和进展有关。GGCT阳性的早期膀胱尿路上皮癌患者更容易发生复发。

Molecular Cloning and Expression of Carotenogenic Genes in Yellowish and Mutant Whitish Loquat (Eriobotrya japonica) Fruits

ObjectiveThe study aimed to explore the factors regulating carotenoid accumulation in flesh color. MethodA loquat mutation （red-or orange-fleshed plant emerged a bud mutation of white-flesh in trunk） was used as material; HPLC analysis of β-carotene content was conducted. ResultThe β-carotene concentration in the flesh of wild and mutant types was 60.9 and 4.6 μg/g fresh weight, respectively. According to the conserved regions of genes from rose family genome, carotenogenic gene fragments in wild and mutant types were obtained. No nucleotide variation of the carotenogenic gene fragments was observed between wild and mutant genome. Real-time quantitative polymerase chain reaction （Q-PCR） was compared and one carotenogenic gene, β-ring hydroxylase （HYB） were considerably suppressed in mature mutant loquat fruits compared with that in wild. The other six carotenogenic genes were also expressed but the expression patterns appeared to be not correlated with the amount of β-carotene concentration in wild loquat flesh. ConclusionThe mutant whitish loquat lacks the ability to synthesize β-carotene because of the transcriptional down-regulation of carotenogenic gene HYB.

Effect of Fish Oil on (-Adrenoceptors and the Activity of Adenylate Cyclase on Myocardial Membrane in Rats

Effects of fish oil on β-adrenoceptors as well as the activity of adenylate cyclase (AC) on rat myocardial membrane were investigated.Supplementation with fish oil had no significant effect on basal activity of AC on myocardial membrane whereas it could markedly inhibit the AC activity stimulated by isoproterenol (ISO). Radioligand binding assays showed that supplementation with fish oil had no effect on Bmax and Kd, compared with saline control. However, supplementation with sheep oil could markedly reduce both the Kd and Bmax, compared with saline control. And the Kd of sheep oil group was greatly decreased than that of fish oil group. The results suggested that supplementation with fish oil mainly affected the activation of AC, not β-adrenoceptor itself.

Changes in Violaxanthin Deepoxidase Activity and Unsaturation of Thylakoid Membrane Lipids in Indica and Japonica Rice Under Chilling Condition and Strong Light

To explore the differences of sensitivities to chilling and strong light in indica and japonica rice (Oryza sativa L), the changes in unsaturation of thylakoid membrane lipids and xanthophyll cycle were studied under chilling condition and strong light. The contents of unsaturated fatty acids of thylakoid membrane lipids decreased and that of the saturated ones increased with the time of chilling and strong light treatment, resulting in the reduction of the index of unsaturation of fatty acids (IUFA). The activity of violaxanthin deepoxidase (VDE), a key enzyme of xanthophyll cycle, also reduced. The content of violaxanthin (V) increased, and the contents of antheraxanthin (A) and zeaxanthin M decreased, the ratio of (A+Z)/ (A+Z+V) decreased correspondingly. Arrhenius analysis showed that VDE was sensitive to both chilling and unsaturation level of thylakoid membrane lipids. Correlation analysis showed that there was distinctly positive relationships between IUFA of thylakoid membrane lipids and the activity of VDE, Fv/Fm, and D, protein content. Lower IUFA values, less fluidity and stability of thylakoid membrane lipids, lower VDE activity and (A+Z)/(A+Z+V) ratio were found in indica rice cv. Shanyou 63 than in japonica rice cv. 9516 under chilling and strong light.

芳香聚酮早期后修饰环化酶的结构分类和功能分析

聚酮是一类结构和生物活性多样的天然产物,根据结构特点可以分为芳香聚酮和复合聚酮两大类。芳香聚酮环化酶是芳香聚酮生物合成过程中一种非常重要的早期后修饰酶,是决定芳香聚酮骨架结构的主要影响因素。根据序列和结构的相似性,芳香聚酮环化酶可以分为不同的种类。本文主要对其中3类芳香聚酮环化酶结构和功能进行了简要总结,从晶体结构、催化反应和催化机制等方面对它们进行了分类描述和功能分析,并结合自己实验室工作介绍了杰多霉素B环化酶催化机制的研究方法。

Expression of pituitary adenylate cyclase-activating polypeptide 1 and 2 receptor mRNA in gallbladder tissue of patients with gallstone or gallbladder polyps

AIM： To detect the expression of pituitary adenylate cyclase-activating polypeptide receptor i （VPCAPrR） and VPCAP2-R mRNA in gallbladder tissues of patients with gallstone or gallbladder polyps. METHODS： The expression of VPCAP1-R and VPCAP2-R mRNA in gallbladder tissues was detected in 25 patients with gallstone, 8 patients with gallbladder polyps and 7 donors of liver transplantation by reverse transcription polymerase chain reaction （RT-PCR）. RESULTS： The VPCAP2-R mRNA expression level in the control group （1.09±0.58） was lower than that in the gallbladder polyp group （1.64±0.56） and the gallstone group （1.55±0.45） （P〈0.05） while the VPCAP1-R mRNA expression level in the control group （1.15 ±0.23） was not apparently different from that in the gallbladder polyp group （1.28±0.56） and the gallstone group （1.27± 0.38）. CONCLUSION： The abnormal expression of VPCAP2-R mRNA in gallbladder tissue may play a role in the formation of gallbladder stone and gallbladder polyps.

Effects of melatonin on the expression of iNOS and COX-2 in rat models of colitis

AIM: To investigate the effects of melatonin (MT) on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in rat models of colitis.METHODS: Healthy adult Sprague-Dawlay (SD) rats of both sexes, weighing 280±30 g, were employed in the present study. The rat models of colitis were induced by either acetic acid or 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas. The experimental animals were randomly divided into melatonin treatment and model control group that were intracolicly treated daily with melatonin at doses of 2.5, 5.0, 10.0 mg.kg-1 and equal amount of saline respectively from 24 h following induction of colitis in rats inflicted with acetic acid enema and the seventh day in rats with TNBS to the end of study. A normal control group of rats treated with neither acetic acid nor TNBS but saline enema was also included in the study. On the 28th day of the experiment, the rat colon mucosal damage index (CDMI) was calculated, and the colonic prostaglandin E2(PGE2), nitric oxide (NO), as well as the iNOS and COX-2expression were also determined biochemically or immunohistochemically.RESULTS: CDMI increased to 2.87±0.64 and 3.12±1.12respectively in rats treated with acetic acid and TNBS enema,which was in accordance with the significantly elevated colonic NO and PGE2 contents, as well as the up-regulated colonic iNOS and COX-2 expression in both of the two rat models of colitis. With treatment by melatonin at the doses of 5.0 and 10.0 mg@kg-1, CDMI in both models of rat colitis was significantly decreased (P＜0.05-0.01), which accorded synchronously and unanimously with the reduced colonic NO and PGE2 content, as well as the down-regulated expression of colonic iNOS and COX-2.CONCLUSION: Melatonin has a protective effect on colonic injury induced by both acetic acid and TNBS enemas, which is probably via a mechanism of local inhibition of iNOS and COX-2 expression in colonic mucosa.

Pituitary adenylate cyclase activating-peptide and its receptor antagonists in development of acute pancreatitis in rats

AIM: Pituitary adenylate cyclase activating-peptide (PACAP) is a late member of the secretin/glucagon/vasoactive intestinal peptide (VIP) family of brain-gut peptides. It is unknown whether PACAP takes part in the development of acute pancreatitis and whether PACAP or its antagonists can be used to suppress the progression of acute pancreatitis. We investigated the actions of PACAP and its receptor antagonists in acute pancreatitis on rats. METHODS: Acute pancreatitis was induced in rats with caerulein or 3.5% sodium taurocholate. The rats were continuously infused with 5-30 μg/kg PACAP via jugular vein within the first 90 min, while 10-100 μg/kg PACAP6-27 and (4-CI-D-Phe6, Leu17) VIP (PACAP receptor antagonists) were intravenously infused for 1 h. Biochemical and histopathological assessments were made at 4 h after infusion. Pancreatic and duodenal PACAP concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Chinese ink-perfused pancreas was fixed, sectioned and cleared for counting the functional capillary density. RESULTS: PACAP augmented caerulein-induced pancreatitis and failed to ameliorate sodium taurocholate-induced pancreatitis. ELISA revealed that relative concentrations of PACAP in pancreas and duodenum were significantly increased in both sodium taurocholate- and caerulein-induced pancreatitis compared with those in normal controls. Unexpectedly, PACAP6-27 and (4-CI-D-Phe6, Leu17) VIP could induce mild acute pancreatitis and aggravate caerulein-induced pancreatitis with characteristic manifestations of acute hemorrhagic/necrotizing pancreatitis. Functional capillary density of pancreas was interpreted in the context of pancreatic edema, and calibrated functional capillary density (calibrated FCD), which combined measurement of functional capillary density with dry weight/wet weight ratio, was introduced. Hyperemia or congestion, rather than ischemia, characterized pancreatic microcirculatory changes in acute pancreatitis. CONCLUSION: PACAP may take part in the pathogenesis of acute pancreatitis in rats. The two PACAP receptor antagonsits might act as partial agonists. Calibrated functional capillary density can reflect pancreatic microcirculatory changes in acute pancreatitis.

Cloning,tissue distribution and effects of fasting on pituitary adenylate cyclase-activating polypeptide in largemouth bass

Pituitary adenylate cyclase activating polypeptide （PACAP） has a wide range of biological functions. We cloned the full-length cDNAs encoding PACAP and PACAP-related peptide （PRP） from the brain of largemouth bass （Micropterus salmoides） and used real-time quantitative PCR to detect PRP- PACAP mRNA expression. The PRP-PACAP cDNA has two variants expressed via alternative splicing： a long form, which encodes both PRP and PACAP, and a short form, which encodes only PACAR Sequence analysis results are consistent with a higher conservation of PACAP than PRP peptide sequences. The expression of PACAP-Iong and PACAP-short transcripts was highest in the forebrain, followed by the medulla, midbrain, pituitary, stomach, cerebellum, intestine, and kidney; however, these transcripts were either absent or were weakly expressed in the muscle, spleen, gill, heart, fatty tissue, and liver. The level of PACAP-short transcript expression was significantly higher than expression of the long transcript in the forebrain, cerebella, pituitary and intestine, but lower than that of the long transcript in the stomach. PA CAP- long and PACAP-short transcripts were first detected at the blastula stage of embryogenesis, and the level of expression increased markedly between the muscular contraction stage and 3 d post hatch （dph）. The expression of PACAP-long and PACAP-short transcripts decreased significantly in the brain following 4 d fasting compared with the control diet group. The down-regulation effect was enhanced as fasting continued. Conversely, expression levels increased significantly after 3 d of re-feeding. Our results suggest that PRP- PA CAP acts as an important factor in appetite regulation in largemouth bass.

Cyclooxygenase-2 expression after preoperative chemoradiotherapy correlates with more frequent esophageal cancer recurrence

AIM： To investigate the relationship between cycloo- xygenase-2 （COX-2）, and vascular endothelial growth factor （VEGF）, and to determine the clinical significance of this relationship in esophageal cancer patients undergoing chemoradiotherapy （CRT）. METHODS： Immunohistochemical staining was used to evaluate COX-2 and VEGF expression in 40 patients with histologically-confirmed esophageal squamous carcinoma （ESCC） who were undergoing preoperative CRT. RESULTS： Fourteen out of 40 ESCC patients showed a pathological complete response （CR） after CRT. COX-2 and VEGF protein expressions were observed in the cytoplasm of 17 and 13 tumors, respectively, with null expression in 9 and 13 tumors, respectively. COX-2 expression was strongly correlated with VEGF expression （P 〈 0.05）. There were also significant associations between COX-2 expression, tumor recurrence, and lymph-node involvement （P = 0.0277 and P = 0.0095, respectively）. COX-2 expression and VEGF expression had significant prognostic value for disease-free survival （log-rank test; P = 0.0073 and P = 0.0341, respectively）, but not for overall survival, as assessed by univariate analysis. expression correlates with VEGF expression and might be a useful prognostic factor for more frequent tumor recurrence in ESCC patients undergoing neoadjuvant CRT. These findings support the use of anti-angiogenic COX-2 inhibitors in the treatment of ESCC.

A CHASE domain containing protein kinase OsCRL4, represents a new AtCRE1-like gene family in rice

AtCRE1 is known to be a cytokinin receptor in Arabidopsis. The AtCRE1 protein contains CHASE domain at the N-terminal part, followed by a transmitter (histidine kinase) domain and two receiver domains. The N-terminal CHASE domain of AtCRE1 contains putative recognition sites for cytokinin. Five CHASE domains containing proteins were found in rice, OsCRL1a, OsCRL1b, OsCRL2, OsCRL3, and OsCRL4. OsCRL1a, OsCRL1b, OsCRL2 and OsCRL3 contain the four domains existing in CRE1, whereas OsCRL4 only contains the CHASE domain and a putative Ser/Thr protein kinase domain. The authors cloned the encoding gene OsCRL4 and found that it represents a new member of the cytokinin receptor protein in rice.